I am a collector of Philadelphia A's memorabilia and cards but I am always hesitant to bid on signed Connie Mack items because it seems like his signatures vary. I don't know if he didn't have a consistent style or if many are fakes. I am looking into bidding on this handwrittern letter, but the signature is awfully different from a JSA authenticated signature in the same hunt auction. Many times I have seen his M in Mack written different ways as well as his C in Connie and K in Mack.
http://huntauctions.com/phone/img69/175.jpg
http://huntauctions.com/phone/img69/539.jpg