George,
My Dads 62 GMC Subn,bought new at Cassel GMC in Patchogue NY,had all the seats in it.
The seats were held to the floor with what looked like flathead carriage bolts,up thru a tubular frame in 4 spots to coincide with slots in the floor,topped off with a square washer,concave on the bottom and flat ontop and finished off with a wing nut.
You could interchange the 2nd /3rd seat location with each other.
I still have the 2nd seat up on a shelf in my garage.
Sadly the 3rd seat was given away back in the late sixties,cause it was taking up space.
And it was only used once or twice.
Believe it or not,except for the upholstery,it looks identical to the 2nd seat in my 51 chevy subn.
hope this helps.
regards steve sr.
Last edited by steve sr; 12/01/2012 1:20 AM. Reason: spelling