I got lucky and had the full-width rear seat come with my '61 when I bought the truck... but it had a pick-up bench seat in it for the front seat. Still does, actually, but it's days are numbered.
For the fronts, I noticed that my truck had the passenger-side mounts ripped out--the sheetmetal was torn away. I wonder if that's why the pickup seats end up in front.
-Brad
