I'm in the process of of putting disk breaks in the rear. I found a place for the brackets to hold the caliper. I can get a bracket for the older style gm calipers are the smaller ones on the later model trucks. I have a set of both style setting on the self in the shop. So is there an advantage of any kind one over the other? And if i decided to worry about the e break at a latter date. does the Cadillac caliper have the same bolt patter as one of these and if so which one?

Skeeter

I've found that the scientific variables of such endeavors are of no great significance. Rather, the meshing of the intrinsic components is of higher consequence.
Be agressive with the sledge hammer and don't mind the pain of compound fractures.

You might want to check the threads on the fluid inlets to make sure the threads are good. Also, later ones might be metric as opposed to the earlier ones.
Terry

caddy calipers require an initial E-brake adjustment
are a pain to bleed
and require frequent use of the parking brake to keep them adjusted.