What is the cast in (Stamped) number on the other spring?
Depending on which motor was in the A body back then had a lot to do with which rear leaf springs they got, 6 cyl. and 318 cars got different ones than the 340 automatic cars got and the 340 4 speed car shad different ones(6 leafs on the passenger side on the 340 automatic cars and 7 leaf's on the driver sides on the 4 speed car, same thing on the 383 cars also.