Finding sealed games for a ps2 collection is hard enough...you want them to be the first print, and you also want them to have y-folds in the sealing. Yet, there is something else you should watch for ; "cutouts".
"Cutouts" are those games that where given away as promo or preview copies, and the manufacturer punched a hole in the UPC before sealing the game.
The UPC is intentionally punched so that the game won`t be returned for a refund or resold in a store. Its one way to tell "This is a not-for-resale copy.".
This is also done with music cd`s, dvd`s and it was also done with lp`s.