Early Barracuda Adjustable Seats?

The first generation buckets are supposed to have spring loaded slides for forward and back plus have ( nut and bolt ) adjustable risers that 2nd generation does not have. Those risers offered a little more forward and back along with tilt angles. I don't know why yours would be different. Slides/tracks missing? Seats bolted directly to the risers?
I have a set of early A-body tracks here from a 65 Dart. Same thing and almost complete ( the little chromed knobs are gone ). The 2 piece nut and bolt risers were rusted away but reads like you have those.
Latches on hinged seat backs appeared in 1968 along with the shoulder restraints.