Currently there is an eBay auction for a PSA graded Popeye Tattoo bubble gum pack that PSA has labeled as the 1956-58 issue.
The reverse of the pack is shown below and the arrow points to the zip code in the address.
The problem with this is that zip codes were not introduced until July 1, 1963 so if an address has one, it was necessarily produced after that date. In this case, this is clearly the 1966 re-issue for this title not the mid 1950 version! Oops!