2nd Gen Non-Engine/Transmission Rear seat construction - what is it?

[KLockliear]

What is the construction like in the rear seat? Is it a wood or plastic bottom with foam above? How thick is the bottom? I want to rivet a strap to the bottom and need to know what I have to rivet/screw into.

 

[SWC]

I have had my rear seat out but have not taken it apart. I believe the seat has a metal frame with fabric on the underside. The underside is not solid with wood or plastic spanning the frame. If you take a drill and a small metal bit you could do some "experimenting". I believe the frame is fairly strong considering the span it has to support.

Stan