I just bought a Metal slug x MVS and the serial numbers were scrached off. The chips are all toshiba and the board says snk. Why would anyone destroy the serials? Also , my japanese SS4:AR has no serial numbers anywehere... The label appears to be official and it also has toshiba chips. I havent opened it up to chack for the snk on the boards though..... Also one of the boards inside the metal sulg x cart has black connectors instead of the normal green of the board.