i'am not to familiar when it comes to the leaf springs. i believe there were a difference when it came to the type of rear axle the car came with ie: jl8, heavy duty options.
www.heartbeatcity.net is a good place to go and check this out. he sells reman. assemblies. if you call him i'm sure he'll be able to shed some light on your question. i've called him a couple of times and he's been very nice and likes to talk about the cars. i think his name is james stibbings, he's got some very rare parts for sale also.