As luck would have it, I was surfing through the trade stimulator listings on e-bay and they have an ABT gun operated via coin slot (I have an old ABT challenger, but they operate off of a penny inserted in the side of the gun as opposed to a coil slot):
ebay.com link: ABT Penny Arcade Shooting Gallery Pistol
Looks like you will be able to tell which, if any, parts are missing.