He’s right, I bent the press I got trying to get the lower ball joint out, then cracked the LCA trying to smack it out with a mallet.
I see a lot of references to the "forged" LCA's on some of these trucks and I should start with I'm not a 4WD guy so I have very little hands-on experience with these, never really looked hard at them, so here's my take. If that LCA was forged I seriously doubt you would have been able to crack it trying to smack the ball joint out. Looking at your picture I see what appears to be a part line right across the middle of the arm.. I wonder if these are cast? Would make a lot more sense. We would hope they're forged, but I'm kinda starting to doubt it.
On the other subject of 1500 vs. 2500 parts compatibility, again unsure on 4WD stuff but on the 2WD's the pockets in the frame are identical, C1500/C2500/C3500. You can swap the arms between all three of those trucks. The only differences are the C2500/C3500 uppers are forged (and do really appear to be forged; they look similar to tubular aftermarket UCA's) and the ball joints have a larger stud in them so the spindle must match.
And yeah; it can be a real bear shoving the control arm into the frame pockets, especially the lowers. When I rebuilt the front end on my old '92 C1500 I used a Porta-Power with the claw attachment to gently spread the frame pockets for the LCA's, then install. Otherwise there seemed to be literally no chance they were ever going to go in.