When the rear was put in were new perches welded on? or did they just pry the leaves apart? I have heard of a couple of people doing this, though it isn't the greatest way to do it.
If you look from the back do they springs bow out in the middle?
Do you mean like center of the springs stick out a bit farther than the ends as if they were stretched to fit? Not really...the pictured spring is a little hard to tell because of that leaf thats sticking out. The other side looks okay. The car came with the rear end and springs in stalled.
I just removed the whole assembly to paint the rear axle housing. When putting the rear back in, I vaguely remember having a little trouble getting the spring mounts into the center hole on the springs at the same time. I'm not 100% but I think what I did was get one side seated, start the u bolts and then get the other side in.