Here is the guide on Peterson's 2007 rookie premieres I put together, easy to match up the results. If the signature matches one of the examples, it isnt real. I also included some real ones for reference.
Adrian Peterson’s Success Leads To More Fake Rookie Premiere Autos | Sports Cards Uncensored
My Adrian Peterson Collection: http://sportscardalbum.com/u/Gellman/a/adrian-peterson
Sports Cards Uncensored - Digital Card Central