No, Berzerk ran (coincidentally enough) the mighty Z80. IIRC it was using the 74181s to determine if there was a match between where it was drawing the ray-blast and where it was drawing the player character and the robots. Thus quickly generating the "hit" condition. I'd have to dig out the schems to remember for sure though.
And yes, it had all the boards bolted onto a vertical panel that pulled out through a tall narrow door in the front of the game. I really liked that; you could work on the logic set without moving the cabinet around on the floor.
That opto joystick was really something. 10,000 games made, 30,000 joysticks puchased for it (to build with, and to support broken ones in the field). If they'd used a centering spring that was *just* a little stronger, or some hard stops (other than the reflective optos, that is), would've been a great design.
Do you remember the optical joystick that "GORF" had? That one was a nice smooth design as well. Midway overdid it a little on the forward current on the emitter LEDs for that one, so they died before their time too. Simple mistakes that nuked a great concept.