Are 70-72 A-body bench seats the same?

I have both, and to my eye the frames look similar enough. I can tell you for sure that the '72 foam is different as it is injection molded and a real PITA to work with. In addition a proper '72 seat has the metal inserts in the upper material. I would believe that any variations from 70-71 in how the material is secured to the frame should be able to be compensated for by a competent
upholsterer.
Daryl