Charlton's says a few notes were perforated "specimen" diagonally three times...but you're right, I don't understand why the word "specimen" is stamped in BLUE on the front, and again in blue, twice, on the back. I have never seen ANY BofC specimen note where the word "specimen" is in blue ink; it's always in red. For the 1954 series I have only seen "specimen" stamped on the back on the note once, near the lower right margin.
Also funny how the auction for this item has no reserve and a starting bid of only $99.99 USD! Book value is $1,250.00! :-?