From my readings on here and Todd’s GuzziTech forums, it seems to have been mostly Stones that were affected. Can’t recall if any Specials or Racers were included or not, but I feel like we would’ve heard more about the Stornellos/Racers since they’re more rare.
Just an FYI: a few of us—at least Jim Hamlin and myself —have seen the insides of these engines that suffered the crankshaft issue (I’m not a pro, but I did take apart one to use for parts on a rebuild). We both found that the issue lie with the clutch-side flange on the crankshaft being milled back too far, leading to excessive endplay, allowing the thrust washer to slip out and lead to even more excessive back-and-forth. The thought we had was not so much that the thrust washer was missing—rather, the washers slipped out and maybe even got mangled to bits before drowning in the swampy sump.