There are really only two options: (1) this was part of the original giveaway run or (2) an original all sticker was placed "after-market" on a normal copy of ASM 184. To me #1 is infinitely more likely. #2 could only take place if someone (a) had access to the stickers and (b) decided to stick it on the exact comic that it belonged upon, only to (c) have it languish as a beater in a $2 flea market box. Wait, what?
To paraphrase Sherlock Holmes, once you have eliminated the impossible, that which remains, however improbable, is the truth.