... and yet I find it interesting nonetheless.
Certed by the PF as having counterfeit IR overprints, this reconstructed full OG irregular block still makes for an interesting aesthetic piece.
The original submitter apparently also included a 1981 PF cert of a (supposed) genuine used example of a Mt. Clemmens (Clemens?) provisional IR overprint.
The only examples I could find at the PF are the certed used example and a single unused example similar to the block, deemed counterfeit.
The only other reference I could find was an auction listing in the 1963 Siegel auction of the Philip Little collection, but unfortunately no lot image.
Even if, on the EXTREMELY unlikely chance, that a legitimate IR overprint would have been used on a Pan American issue (issued only weeks before the tax was repealed), one would expect to see it on the 2-cent denomination, not 1-cent.
Would be an extremely cool item if actually genuine. Instead, merely a curiosity.