What car did these seats come from?

They look like early 70s buckets, but from what, I'm not sure. IIRC the plastic back covers went from squared off upper edges to rounded edges, or vice-versa, mid to late 71? I had an original 71 Challenger but the seat back release buttons don't look familiar. They could be from an early A Body Duster/Demon & might be the original seats to THAT car. I'm also pretty sure someone here will know exactly what they are.