I have no idea with the Atari, but the Exidy is likely either a stripped Circus, Crash or Rip Cord.
Rip Cord would be the rarest of the three but I don't know what they would go for in this shape, Crash is more or less in the $30-50 range and more like $20 in this stripped state (if that), and Circus I've seen go for about $100 working, I don't know what to price a stripped one at.
Keep in mind a lot of Exidy games used PAL chips that haven't been dumped for MAME and to the best of my knowledge aren't available yet, so restoring one without them might be quite a problem.