This is an interesting topic.
On the surface, I'd think that any A body from 1967 would fit another 1967-76 model but....
There may have been changes. Maybe the 2 door models differ from 4 door cars? I thought that I was told that the 4 door cars had rounded corners on the lower cushion to provide more room to get into the back seat.
Only 67-76 2-door hardtop Dart or Scamp. 67-69 Barracuda coupe does not fit, nor do fastback or 2-door or 4-door sedan...
I've parted out several 72-76 A bodies and kept many seats....while not putting tags on any of them to help me remember what they actually came from.