The Musicmaster neck is in, and it shows the wear one would expect...but not abuse. Looks like the tuner holes in the headstock may be a little different diameter than most tuners today, but I haven't had time for careful measurement yet.
I did determine that the base of the neck is just slightly wider than the rout in the bass body which has been cut, but that's not a show stopper.
I'm absolutely stacked up with stuff until May, but hopefully can get started on it then. I still have to figure out which body to use, so I'll check in again when I decide which direction to go with that.