the late 70's CJ axles have bigger brakes than the 80s CJ axles both front and rear (10" smooth drums, 11" finned), and biiger and thicker discs in the late 70s. Also the earlier D30 has a better 6-bolt caliper bracket, compared the to the later 2-bolt versions. The earlier axles use Warn premium lockout hubs, later ones use standard. When I swapped to widetrack, I stripped all the 80s crap from the widetracks and used my '77 knuckles and brakes.
Oh, if the rear AMC20 is 2.73 ratio, thats pretty undesirable as that ratio has its own carrier.
Whats it worth...? whatever someone will pay for it.