Quoted from cait001:

I heard back from the production company (Advanced Animations) and they said Grossology exhibit has a smaller and a larger touring configurations, and that only the larger setup contains the Gas Attack pinball machines, which are confirmed to still exist.

Quoted from kbliznick:

I was hired to repair these games when the exhibit was here in Phoenix a couple of years ago. They were in pretty dimsal shape at the time. I had to rebuild the flippers and pops and even fix an incorrectly wired lamp matrix on one of the games (glad they had them side by side)
While the playfield and cabinet are from a Capcom Breakshot the board set is actually a Stern Whitestar. All the wiring connectors from the playfield harnesses have been cut and recrimped to fit onto the whitestar driver board. I wish I would have thought to copy the Roms out of it.
The code was super basic. Only 1 ball per game, single ball play, set to free play. No modes or multi-balls or anything IIRC. You just got to flip the ball and it made body noises and gave you points for hitting the switches.

Quoted from rygar:

Clay Harrel might have the roms. His repairs of those games are documented on pinballninja.com blog (repair #640, #790 and #791).

Quoted from zacaj:

JM is great!
For legal reasons I think they limited the matrix conversions to 3?