I was going to trade in my brother's and my old DS lites for Gamestop credit to buy a 3DS later today, but it occured to me that since we got them pretty much the christmas they came out. Needless to say through all this time the receipts are long gone. So... getting to the point, do I need a receipt or to call the store ahead of time? Or can I pretty much just walk in with them in my pockets and expect them to put it on my gamestop account no questions asked?