bucket seat frame abody
I have had 1972 & 1973 bucket seat backs in the shop & I have not seen that rod, ever.
I have also had seats in the shop with plastic rear covers & 1973 model year date codes.
When it comes to bucket seat frames, no such thing an A, B or E - same frames inside the same time period.
It is the upholstery, foam & tracks - but those can be changed depending on type.