72 Demon seat backs?

Those are really  nice.
The front seat in the car now is a high back bench seat and I've seen high back bucket seats with plastic backs, and am wondering if that is how these might have been equipped. I guess if I took them to a shop they could fill in the indentation with some foam and use the old covers for patterns for the new ones. I've seen guys have used Chrysler convertible seats as they have the shoulder belts incorporated, but they seem to be hard to come by these days. I think Foxbody Mustang convertibles are like that too.