I'm pretty sure that the ProcCard in the CrescendoPB Bag was from "Beater," my maxed out 1400c/166. I'm holding in my hand ATM and it's a QFP Proc.
I'm almost certain they do, I had a running conversation on 'fritter, back in the day, with a notorious DuoHacker about the source of his QFP G3 collection. IIRC it was a boxy green assembly for something not Macintosh related and it was an iffy proposition to strike QFP Gold or just wind up with another fetid BGA POS in your hands.
IIRC this was the same guy who managed to transplant the Video Controller ASIC from a 1400c (?) onto the underside of the Duo MLB and get it to function properly. It's too bad there's no way to search the "old guard" 'fritter archive. I was helping him look for the resistor pack that controlled the bus multiplier and I trust what he told me, he knew his stuff!