Scott 361 Bluish Paper

I'm so lucky that I inherited it from my grandfather and look what I found.

Congratulations.

Used OG??????
Why remark 'previously hinged' for a used stamp?

Now you deleted the picture of the certificate and (almost invisible) stamp and you deleted the text about finding them leaving only the word "lucky."

I've contacted the OP and waiting for them to reply. If we can't recover the original scans/pictures, I will delete this thread as it is entirely useless without this information. Waiting ...

OP was lucky to have inherited stamps and posted a photograph of a Scott 361 certificate by, if I remember correctly, the Philatelic Foundation stating it was genuine.
The stamp, photographed with the certificate, showed tiny and fuzzy. It did look somwhat similar to the one on the certificate. But the certificate raised questions.

First of all, there was a picture of a cancelled (barred numeral oval) stamp with to the right of the stamp a number equal to that on the certificate but almost encroaching on the stamp.
The description was "used OG" but it was indented in a manner that it once could have read "unused OG."
The opinion mentioned it had been 'previously hinged.'

A clear scan of the certificate and of the stamp might have been informative.

Edit: looking at the PF database, the stamp shown on the certificate posted by OP does not appear in their database.

I restored the post.

That dog (the alleged 361) won't hunt.

"Lovestamp" sounds like the name of a Bond villain, but he or she was none too clever .
Good quick work of him agent NSK.

That is some of the sloppiest skullduggery I have ever seen.

Yes, I thought I had found a jewel #128517; When I got the note on the certificate, I immediately deleted it because it doesn't need to be online when it's not real. When I went online to search and compare, I saw for myself that there was something wrong here. When I then deleted the picture, it was unnecessary to bring it up again. Why should such a picture be out there when it's not real? I still have the stamp and it's not a fake because the envelopes it was attached to are still there #128517;#128517; Maybe I got lucky and it's 361 #128517;#128517;

First, you should realize that many, many new users come here with what they believe is a huge find. Some actually do pan out, but the majority are not worth much. That's just the way it is.

In your case, if your grandfather had something sent to PF in 2000, then something is definitely wrong here. The PF cert has some definite issues, the most obvious being a note that says "it is genuine, previously hinged". That note is usually only applied to Mint stamps, not used ones. So we now think that there is something wrong.

NSK did a good job checking the PF database, and found that the Cert number 348989 does NOT match what you have. This means that someone was trying to deceive someone, and that was probably the seller trying to deceive your grandfather. We've seen it happen before. Too bad.

But, as you are thinking, it still may be true that you have an authentic 361. Highly doubtful, since only two used copies are known, but possible. In order for us to give you a better opinion, you would need to provide a scan on an orange background. Photos will not work, and the scan would have to be in focus.

In your grandfather's paperwork, did you find a receipt for the purchase of this item?