that Rear Seat is from a 60-62 GMC or a 60-66 Chevy Suburban, 63-66 GMC back seats had the slider channels. hope this helps.
x2
That seat will also work as a full-width middle seat for a 2-seat Suburban. At least on '60-'62. I've got a '62 with solid rear windows, sliding middle windows. It has both sets of mounts in the floor for the abbreviated middle seat in a 3-row situation, and the full-width seat for a 2-row.
The guy I bought it from didn't realize his '61 had the same mounts, until I pointed that out to him--AFTER the seat frame was in the back of my truck!
Poor guy is probably still hauling his kids around on a short middle seat.
-Brad
