No difference in left or right original 13 leaf, or factory competition 10 leaf springs.
Hard to find original springs without cracked leaves or major distortion at "U" clamp area.
Left / right difference came with aftermarket "offset" springs. (typically 3/4" offset) Not a factory part. Were many sources for these; hard to "match" a set.
I have many original 13 leaf springs, all requiring disassembly and re-arching.