Hi,
I recently purchased a sheet of #5019 stamps. As usual, I used short UV to check for authenticity.
I placed another #5019 I had before on top of the new sheet for comparison.
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For this, can I reliably determine the stamp sheet I just bought is fake? The seller, who has no negative feedback regarding counterfeit stamps, claimed they purchased it directly from USPS.
This stamp is from 2015, which was nine years ago. Do you know when the first counterfeit stamp appeared in the US market?
Thank you