Some famous modified Rics:
McCartney's 4001S, stripped and sanded down (against the grain) to bare wood, then the "cresting wave" in the horns rounded out, and a zero fret added.
Chris Squire's '64 1999RM - according to Squire the body was shaved thinner before it was refinished in cream white. Some pics, however, suggest that the bass is not thinner than a standard Ric bass. It was also wired in stereo.
Roger Glover's '72 Jetglo 4001, was all original for the Machine Head recording sessions, then the neck toaster was replaced with two slanted Fender J pickups.
Renaissance's Jon Camp's modified Ric 4001 "Great White".
Cliff Burton's 4001 with the Gibson mudbucker and Fender J pickups.
Mike Rutherford's double neck Ric... a bass and a 12-string cut and glued together.