[youtube https://www.youtube.com/watch?v=HX4srzZwj2s&w=600&h=338] How appropriate that on the day Panini America's 2012 Prime Signatures Football goes live, one of the most prime pass-catchers in NFL history stops by company headquarters to sign some autographs. When he was done, Oakland Raiders legend and Heisman Trophy winner Tim Brown spent a few quality minutes discovering some of the finer points of Prime Signatures.…