Lower Control Arms 1971

[exploderjim]

I was wondering I ordered new lower control arm shafts for a 1971 Cheyenne Super BB 402 1/2 ton long box C10 and received shafts with screw type ends on it. I took mine apart to find mine were the ones with rubber bushings. When I looked up the parts the bushing style was like the 73 bushings. The alignment shop ordered the correct rubber ones from Moog and said mine were not interchangeable. Is this some how a different set of lower control arms or was there another option? I'm confused as the part supplier says the screw type are the only ones for my truck and clearly they are different. Any info would be appreciated.

Jim