I Have A PNC With A Plate Number On 2 Adjacent Stamps

I am new to SCF, this is my first post. I have a PS6 of Scott # 2813b which I bought at the post office many years ago before I started collecting seriously. I have found that the plate # B1 appears on 2 adjacent stamps. This is a SA coil, and the B1 plate # indicates that the design is also in a booklet stamp. In addition, the spacing of the stamps on the backing paper is wide (about ½ inch), which suggests that the issue was designed to be used in a vending machine (my guess only). One experienced collector has suggested that this may be a forgery -- someone carefully placed 2 plate # stamps next to one another on the backing paper. To me this is unlikely because I know that I am the only owner of this PNC since it was in the post office. The backing paper is intact so that it is unlikely that this is a seam where the printer joined 2 rolls together. OK, does anyone have any other explanation, or do I have a rarity?

*** Moved by Staff to a more appropriate forum. ***

I believe on this issue it is still possible for your strip to be the seam where to rolls were put together. Two rolls of stamps that is, not the backing paper. I think the stamps were applied to the backing paper after being printed.
Is it possible for you to post a scan?

Peter

I will photograph the strip, front and back, and post it later today. I should have included a photo with the first post, but that was my first post ever and I didn't think of it.

" I bought at the post office"

If you are claiming you bought them at a Post Office, how can this be true as they were only available from the national mail center in Kansas City (except possibly in Washington D.C.?)

"the spacing of the stamps on the backing paper is wide (about ½ inch), which suggests that the issue was designed to be used in a vending machine"

The were for use in stamp affixing machines.

eyeonwall and Peter--

You're correct on this point. I bought it 24 years ago, and at that time everything I acquired was from the USPS, so I presumed I got it from the PO. I know for sure that I did not acquire it from a person or a dealer or anyone else who could have tampered with it. Thanks for the info about the stamp affixing machines.

Peter -here is a photo: