I also tink that the purpose is to find a new owner ,who may want to pay such high price only to have in his collection such rare stamps,but as all similar to this adds there is catch.
I should apologize, I had not been correct in my quote, he doesn't say that he has suspicion that they are genuine this only my interpretation.
It is interesting to mention that the add is being followed by one member of the website when ,actually they are being offered as they were bought by the seller -reproductions .
In the short description made it is pointed that because they do not have any document with which he can prove his claims ,he is selling them as" it was offered to him " off course on much lower price than the real one.
I'm also surprised ,why would he bother to put them at add at internet when he could receive a document and sell them were he wants if there is no catch?
Here is a link to the original add-
https://www.delcampe.net/en_GB/coll...2951745.html