crossmember swap

[71/454]

I'm sure this one has been done a million times, but I have looked and can't seem to find a definitive answer, could anyone please help me I don't want to assemble a newly painted truck and have it unable to be alligned. I have a 71 c10 2wd with 73-87 lowered spindles a 73-87 cross link pitman, idler arm, and tie rods, and 73-87 upper ball joint in the 71 a-frame and a stock ball joint in the 71 lower a-frame. Everything bolts together and works but I have not had it alligned, other than a tape measure(drives not bad actually). I am starting dissasembly to put the truck into paint and have found the steel bushings in the a-frames to be completely worn out. I have a set of upper and lower a-frames from 73-87 with rubber bushing and wish to install them. Everything I find has talk of swapping the entire crossmember, is this nescessary to get a proper allignment? Or can I just swap all the parts. I looked quick but the croosmembers look to be the same. Any and all help is appreciated thanks.