This is an unidentifiable replacement note.  It is listed in the Charlton catalogue as a replacement, so the holder is correct.

I didn't mean to doubt the correctness of the holder, but to me it looks like "just any serial number".

I guess I'm beginning to understand the question "if a tree falls in a forest and nobody hears it, does it make any sound then?"  I mean, what makes this note a replacement, other than literally "somebody says it is"? To me it holds no premium value this way. Buy hey, that's just me 

I am interested in the three BC-55a notes. AUM, AUN, AUK.  What are you asking for them?
Thanks,
Ken

Usually as different prefixes but the same series/denomination/signature.  So FMI inserted into FMH, for example.
A brick is 1,000 notes.  A bundle is 100 notes.  Bricks usually consist of 10 bundles, or could just be 1000 notes.  A block is a shrink-wrapped set of four bricks.
The catalogue was (still is) published annually.  Depending on the timing of the reports of insert notes being found, and that of any corroborating reports, and the timing of each catalogue, it could be just a few months, or multiple years or anywhere in between.
It was actually Paul Wallis who started this site (c. 2000) several years before I showed up.  It was only about a decade later that control of the site effectively passed to me, and did so completely following his death.  In 2018, the site was transferred to a new owner.  I no longer have any administrative role here whatsoever.

Thank you for that info BWJM, and for your knowledge, contributions to this site and to the hobby.

Sorry to suddenly resurrect an old thread after a 14 year hiatus, but this is an important topic that is still relevant and keeps coming after all these years.

Unsurprisingly, X-Savior's original article from 2007 is no longer accessible, and Hudson A B's website has been retired. Does anyone still have access to any of these original articles?

I wanted to ask how these would appear: as Macdonald $10s in bundles of Desmond $10s? Or as Wilkins-Poloz $5s in bundles of Wilkins-Macklem $5s? Or as FFG $10s in bundles of FFKs?

Usually as different prefixes but the same series/denomination/signature.  So FMI inserted into FMH, for example.

How big are these "bricks?" Some of these ranges are large, comprising hundreds of thousands of notes.

A brick is 1,000 notes.  A bundle is 100 notes.  Bricks usually consist of 10 bundles, or could just be 1000 notes.  A block is a shrink-wrapped set of four bricks.

Also, I would imagine it would take time for these to be discovered, reported, verified, and then published. How long would it take for some of these replacements to appear in catalogues, a few years?

The catalogue was (still is) published annually.  Depending on the timing of the reports of insert notes being found, and that of any corroborating reports, and the timing of each catalogue, it could be just a few months, or multiple years or anywhere in between.

I believe insert replacements are one of primary reasons @BWJM started this site.

It was actually Paul Wallis who started this site (c. 2000) several years before I showed up.  It was only about a decade later that control of the site effectively passed to me, and did so completely following his death.  In 2018, the site was transferred to a new owner.  I no longer have any administrative role here whatsoever.

I did not answer @rxcory's question b/c I was waiting (& hoping) someone more knowledgable would step up & reply.

When I got back into collecting (in 2003) I met @BWJM & he told me about several Brick searchers coordinated searches & their discovery of "insert replacements." Later, I met many of the key people involved in this enterprise.

Here is one of the better threads that explains what transpired over the course of several years & I believe insert replacements are one of primary reasons @BWJM started this site (for continued correspondence/verifications during the roll out of the Journey series). It also continued for the polymer series but was abandoned by the time the BoC released the 2015 commemorative $20 (I believe).

Please check out this thread to further understand what happened (how many brick searchers tracked BoC insert replacements & compiled data for the Charlton catalogue & this site on the SNDB):
https://cdnpapermoney.com/index.php?topic=5160.0 

Hope it helps answer your questions!

PS: I would try to explain it myself but I was never a replacement collector so I have only repeated what others (who were involved) have told me.

Thank you!! I had done an exhaustive search here before posting the question, but obviously missed that thread somehow.

I was actually on a similar puzzle lately. I found a note on eBay that had "Replacement" on the header but so far I have not been able to find any clue as to why I would believe this note to be a Replacement. It is a PMG slabbed note and I trust PMG know what they're doing, but to me there is no evidence.  It's about this note if anyone wants to find out for themselves. https://www.ebay.com/itm/193879118988 How can I see that that is a Replacement?  I can't.

This is an unidentifiable replacement note.  It is listed in the Charlton catalogue as a replacement, so the holder is correct.

Great finds @Breanna72.

I got my first Lane-Macklem INS only a few weeks ago but haven't seen any INY or the new prefixes you've been getting.

The 2009 Journey ARW high SN is a year change-over too!

Cool Balboa coin from Panama!

That BanknoteMate app looks very promising! Now I've got to investigate further. If anyone uses it- pls PM me so I can get a better grasp of what it does (how effective it is). Thanks 

Thanks for sharing @Lighthouse250 & welcome to the CPMF! 

I did not answer @rxcory's question b/c I was waiting (& hoping) someone more knowledgable would step up & reply.

When I got back into collecting (in 2003) I met @BWJM & he told me about several Brick searchers coordinated searches & their discovery of "insert replacements." Later, I met many of the key people involved in this enterprise.

Here is one of the better threads that explains what transpired over the course of several years & I believe insert replacements are one of primary reasons @BWJM started this site (for continued correspondence/verifications during the roll out of the Journey series). It also continued for the polymer series but was abandoned by the time the BoC released the 2015 commemorative $20 (I believe).

Please check out this thread to further understand what happened (how many brick searchers tracked BoC insert replacements & compiled data for the Charlton catalogue & this site on the SNDB):
https://cdnpapermoney.com/index.php?topic=5160.0 

Hope it helps answer your questions!

PS: I would try to explain it myself but I was never a replacement collector so I have only repeated what others (who were involved) have told me.