It's just all Proofs that I have ever seen have a certificate of authenticity and is in a case so no one can touch it with there fingers, when it is not in a case that is usually a coin for circulation and not a proof, so what I would like to know is do you have any paper work to prove this is a proof??? Please get back to me when you get a chance, Thanks!
A little education in US coinage is in order. The US does not distribute individual proof coins except commemoratives.. All individual proofs of standard coinage come from broken sets. Since 1968, all US coins bearing an "S" mintmark (San Francisco) are proofs. San Francisco does not issue coins for circulation. A proof coin is a special strike and will always be one despite how it is displayed or cared for. Even if it was still in circulation, it would still be a proof albeit probably not a very desirable one. In this case, the "S" is proof of being proof.