Straw purchase?
That would only be the case if he was purchasing for someone who can't legally purchase one themselves. Firearms can be purchased as gifts.
Not according to this article... http://www.npr.org/2014/06/16/322650543/supreme-court-rules-against-straw-gun-purchases
Straw purchase?
So you think he drove to some gun shop in Philly and said, "I'll take 10 of those Berettas. Have them engraved with these numbers and I'll be back on Friday to pick them up."?
More likely there's someone affiliated with either the Eagles or his agent's company that can go direct to someone within Beretta. They pull the nicest pieces of wood they can find, manage the engraving, and send them to an FFL dealer within each player's state of residence. All CW does is sanction the purchase, doubtful he even signs the check.