[Model51]

Yep. I had the same thought and it does make sense. Doing all the research and having the Ford Engineering Drawings for the seat base parts I can only come to one conclusion that those metal plates weren't part of the seat base for trucks, only pickups. Since the difference is the seat base support, Ford engineers must have thought the seat riser put too much stress on the plywood in that area, but that's just speculation on what they were thinking in the day.