Well it seems as though I was right. I went and took a look at the machine, which turned out to be a complete junker. Apparently his "working" machine had more than a few issues - including lack of flipper mechs that were "borrowed," zero response when plugged in (possibly just a fuse), about 75% of the playfield artwork, a 6.5/10 cabinet, and broken rubbers and plastics. The only thing the machine had going for it was a 9/10 backglass. I'm not sure what he payed for it or how long he had it, but I'm sure he grossly overpaid. I told him if he ever wanted to get rid of it that I would keep in touch and give him $75 to haul it away. He thought he was sitting on a pile of gold. It was more like a pile of shit.
What did we learn? I was right, but could have handled it a little more delicately. Next time I contact someone about an over-priced machine, I'll be a little more courteous. We also learned that (more often than not) people don't know what the hell they're talking about.