One problem:
The USPS also applies that barcode after it reads the address. It is the location the letter is going TO. Not who sent it.
Yes, return envelopes in your bills have that type of barcode preprinted. But look at your Christmas card envelopes that you received. They all have the same barcode applied after they were mailed. It is the barcode for your address.
I’m not saying this letter isn’t a scam. Just saying the Twitter guy doesn’t know USPS facts.
Ok. but stamps are not cancelled AND the stamps are from a block in 1975.