As a general hint when trying to identify unusual stamps - you can often find out a lot by using Google. So for instance for the Tunis field post stamp (the swastika on palm tree), I used Google image to search for SWASTIKA PALM TREE STAMP. The top left image in my search was the stamp concerned - clicking on this, and then following the link to the website, identifies it as a Tunis field post stamp from 1943.
Similarly with the Bergedorf stamps - by doing an ordinary Google search for BERGEDORF STAMP, I could get to a Wikipedia entry about the 5 stamps issued by the small town of Bergedorf.
But of course this tells you nothing about forgeries - for which expert knowledge is needed!
Hi brad, welcome. I know next to nothing about these, but from reading this thread (which you did also) it sounds like you need to send it to a stamp expertiser and pay to get a certificate of authenticity.
Revstampman has not been on here for a while now. I don't know if he is anywhere else.
Try starting a new topic and posting a good pic or scan of the stamp (scans are preferred) and maybe someone here will chime in on it or where to get it expertised. Some expertisers are bettera t some stamps than others.