Lower control arm differences??

[Tahiti or Truck]

I have a 66 C20 with cast lower control arm shafts. While I had the motor out I noticed that the lower control arm shaft mounting bolts look like they are placed in the same location as the newer 67-84ish on the crossmember. I would like to do the caster mod of relocating the lowers forward to increase caster to a set of newer style lowers. My question it can I order the saddles, locating pin and u-bolts from LMC and simply bolt them in? That seems a whole lot easier than replacing the cross member.