Oh really.. Well, I did some research about the "Dwayne Johnson" signature and found him signing this piece IP. I'm 99 percent sure I got the real deal.
Sent to the G.I. Joe 2 set. They wrapped the film up on Nov. 12. It got here today (Nov. 14). Makes plenty of sense for him to do a mail cleanout at the end.
http://www.youtube.com/watch?v=Lp2pYVjhJpo