What the title says: Are leaf springs interchangeable between the two models; in particular, for a 1980 RWD pickup?

Also, i'm looking to simply swap out the rear leaf springs; any recommendations?

 

i would think no, I know there different on chevys, same length and dimensions but less springs in the pack on 2wd. So thats what id do, measure the springs from eye to eye, measure width of spring, and measure from eye to center pin from both sides, then count the springs in the pack, if measurements check out then its possible to take springs from one and add them to the other if you need to.