Are all a body ball joints screw ins?

The upper arm doesn't see a lot of stress. I have had to weld a few in, but you have to be careful not to destroy the bearing inside with too much heat. I did a little more than "tack" them in tho.
I long time ago Mopar made rings to install on the under side, and press them against the bottom of the arm. I haven't seen those in a few decades now, but you might be able to fab some up.

The thing is cheap BJs don't go for 100,000 miles like the oems mighta. I have seen some barely make it around the block. If yours only make 15000 miles,and you more than "tacked" them in , then that was a waste of time, and now you're shopping for arms again. So, IMO, if you got spares, use them.
The bushings should survive the transplant. But if they are not Problem-Solvers, I would ditch them.