I beleive that the value of a regular HOG prefix note of $8 would be ADDED to the radar premium of $80.00 making it worth $88.00
2 digit radars are usually $80. Most people don't add the regular note's BV ($8 + $80 - $88).
Remember that the Charlton is a guide: book value may be asked but that doesn't necessarily mean that's what he'll get. The BV typically means the highest amount a collector will pay because that person wants that particular note.
If it was an insert in the higher range it would be worth the insert value of $100 plus the 2 digit radar premium of $80.00 for a total value of $180.00.
Yes this generally the case in this rare situation. Most insert/radar collectors would offer something in the ballpark of $180 (but again it would be up to $180 on a good day!) The note would have to be GEM and flawless to command the full book value. There are many variables that can factor in -- but the one rule you can count on -- the rarer (& higher grade) the more likely for it to reach book. However, there may be collectors who only collect 1954 radars (or solids), or X and asterisk inserts. These collectors either wouldn't be interested or would offer well below book.