Yes, there are at least a couple of variations of rear brake cable assemblies available. The OEM unit has a cover over the last few feet of cable as it enters each rear backing plate, while some aftermarket versions do not. As long as the cable is the correct length and has the correct spring and stop at each end, then you're good to go.
With most aftermarket replacements, you'll have to reuse the saddle that mounts at the center of the cable (and attaches to the threaded rod/front cable) and you'll also have to reuse the hangers. That was true of the EIS cable that I got for my 54.
Two and four door rear brake cable assemblies are the same and I think they're the same between standard and hydramatic.