Don't worry about it...........u know they are not forged, what I think happens is that some players (KH prolly included) tend to change their sig when presented with a serious amount of cards. I know sonny bill williams used to do this a lot and I have heard of other players doing it on a regular basis.
Isnt the sig you got a lot smaller than mine though? I had 9 cards for him.
I know of some players who change there sigs. Hunt, Sonny Bill, Carl Webb, Jarryd Hayne. I just wish a player would keep there sig the whole career. Bowen has shortened his sig.