I saw the Allman Brothers when they were still intact sometime in the very late 60s at Hudson Valley Community College, warmup band was Jay Giles band. They were both still undiscovered enough at that time to be playing at a tiny junior college venue like this.
It may be that Hexis removed one of these when he converted Gibby's original PL700, as he did a complete chassis conversion as part of that effort.
Worth asking.