Quoted from ForceFlow:That still doesn't answer where the big cabinet start start button went, though
or the 2 missing flippers. Where the flippers should be, it has different ball wire guides, and plastics that seem to match the artwork. I suppose its possible that some operator, removed 2 flippers, made custom wire guides and plastics AND while he was at it, nicely and cleaned patched the start button hole and proceeded to then match the paint/art perfectly, but that seems like a stretch.
I could believe that being the first atari pin, and possibly a prototype, they used a midway coin door because it was available. The actual production coin doors weren't ready yet, but they needed a working prototype. Makes sense to me at least.
I am not an expert by any means, especially when it comes to atari pinball, but I'm gonna have to go with Occam's Razor on this one and bet it is a prototype of some sort. You'll definitely want to verify with somebody who would know though. I wonder if Mark or Steve Ritchie might have some answers.
Definitely document as much as you can and be sure to share with IPDB