First, let me say hello and I'm glad I found you all. I just opened a pawn shop and will probably need lots of help in the coming years and hope to offer some support if possible but I know very little about paper currency although I am willing to learn and probably should. My question is this. Someone came in with some bills and only wanted $150 for the lot so I bought them. In the top right corner of the $100 reverse, there is a small stamp that kind of looks like a state. Is this something that was stamped by someone or did the bill come this way? Just wondering and again thanks for any help in advance.