Yeah, cause its going to take trading off your first born to find a working sound board.
Conversions are bad enough, but its worse when people don't bother to do a decent job of it. If the idea is to get rid of the old game, then everything associated with the old game should go as well. There are a few exceptions, such as when the old and new games are they same genre. For example, if you put a space shooter into an Asteroids or a Gorf, you can leave the side art and still have it look halfway decent. But, when you do a half-ass job, it usually looks like one.
It would be interesting to hold a contest on here - sort of like the best restoration thread at coinopspace, except the goal is to take a decent fully original game, and do a best conversion to some JAMMA game, like was done in the 80s.