I recently bought a bunch of proof sets on an auction site. When I received the shipment they send a little "extra". I thought that was nice of them. The envelope said 1836 Mexican coin - cute. I took it out and looked at it - "it" was tiny. I eventually decided to take a closer look, one side was all sticky and I couldn't really see anything, so I cleaned the sticky side and peeled off whatever it was and decided to give the coin a little vinegar treatment. When that was done I took it to the scope and found. (I think I'll check out their auctions again)
I am thinking that was a loss leader. A generous gift that will make you look forward to doing future business with them.
I don't think so. They literally thought it was a Mexican coin, and in the condition I got it I can see why. If you only look at the eagle, it does resemble the eagle on Mexican coins. Since I got some decent deals I will buy from their auctions again. I got two 1974 proof sets for about $15.00 if memory serves, and both had the clear S mint marks.