Jersey looks pretty nice to me. I cant really say if it is game used or not since Im definitely not an expert. Prova Group used to have a website where you could verify the serial # from what Ive read. I would say $300 for a future HOFer is pretty decent considering retail authentics cost $250+. Get him to send you some additional photos of the shoulder marks and maybe you can get a member here to try and photo-match it. Im not sure what size he wore but Im sure a 52 is close. Heres a photo from 2005