Ah hahahahahaha... thou shalt check voltages.
So, the caps are all 100V rated. And the RA4,5 and RB4,5 all are correct readings.
Checked the IC2 pins, and things just didn't seem right. The power rails were pegged at 16.5V or so. So, looking at the schematic, I noticed D2 is what derives the negative power rail for IC2. It's supposed to be a 4.3V Zener. What has the previous owner soldered in... a 1N4006. DOH.
Swapped it out for a zener that was close enough (measured it at 4.27V), and fired things back up. Bam! It works! Went through the calibration process in the manual, and everything checks out. I've got some replacement, matched 3055's on the way that I plan to swap out (what's there are 3 ancient RCAs (hfe of 30's to 50) and a new ST (hfe of 250!!!)).
But otherwise, it seems to work great. Total outlay in parts... about $3. I had the zener, the cap, a replacement LM324 and 723 in my parts bin. Just had to buy the Q2. If I include the 3055's on the way (which Radioshack is blowing out for $1.50 each), I'm out $9.
Thank you floodydust!!!