[66-PMD-GMC]

All right..
after a little detective work I found out a few things.
The bed I have has a front and rear bed rail and one in the middle, sort of.
The PO of this bed told me he had no idea what year it was but it was on his 67 when he bought it.
Looks like it was converted from a wood floor to a steel at some time.
No bed rails are spot welded to anything and the floor looks like it never really had anything spot welded to it ever.
I'm going to wait and reset the cab on new cab mounts and then work on the bed. Probably 5/8ths ply under the sheet metal.
Getting a camera tomorrow and I'll photo the whole thing.