Pictured in this listing is an example of this game that left the factory without the add-a-ball function. The lower right corner of the inside of the backbox shows the holes in the insert for the add-a-ball lamps have no sockets or wiring. Above these holes is where the add-a-ball stepper unit is missing and would have been mounted. The jumper plugs for this option are not present in the upper right area. Reportedly, the schematic for this particular game does not show any AAB steppers, coils, relays, or lights for this feature, while its backglass is silkscreened to show the add-a-ball numbering. We don't know how many of the games in the production run left the factory without the add-a-ball function or the reason for its omission.