I think your right on . I dont like how small the signature is and I personally dont like how the signature looks but that doesnt make it not authentic. I havent gotten Stans autograph in person in over 10 years. I did purchase some from a show and that was a long time ago as well . That can be how his new in person autograph looks . Do you know where the person got it signed, what year and when . Stan sells his autograph on his own website.
Here is the link stan-the-man.com . Look at those autographs as Im sure they are authentic.