Just curious about something.
Did you replace the front of the game? I thought all Atari cabinets had over/under coin doors, but that has a cutout for a midway sized one.
EDIT
Oops, never mind. Just went picture hunting, it appears Atari switched from square doors to over/unders sometime during 1981 (after Centipede). So Centipede, Missile Command, Tempest, and Asteroids have square doors (along with the rest of the less common early Atari stuff), while all the other Atari games have over/unders.