So it turns out that my Demolition Man is definitely a prototype!
It had proto ROMs in it, four unlabeled inserts, and all red light boards, but some remained unconvinced.
But now it has come to my attention that it has a WPC-S CPU board in it! (Which would be why the set of home ROMs I ordered for it doesn't work right, specifically the CPU ROM.)
Then I found this 2004 rgp post from Ted Estes himself: "Demolition Man prototype games used the security chip. There may be a few of them out there still. My memory is hazy on the details -- I put regular WPC CPUs in quite a few of them after we finished with the initial development of the Security CPU and code.
"Sample and production games all used the original WPC CPU."
So there is at least one "out there" -- mine!
Anyway, I gather that I could simply drop an original WPC CPU board in there to use the new ROM, is this correct? (I could figure it out by checking connectors and schematics, but many of you would know the answer offhand, and whether any other changes would be needed.)
Interestingly, with the new ROM (for WPC), the (WPC-S) CPU booted into attract and the menus and lamp tests work fine, but the switch matrix is dead. I didn't try firing any solenoids.