For all intent and purpose the axle shafts and birfs from the 1990 and later 70 series are the same as the pre 1990 units.
The birfs are different, but not by much. The strength, I would hazard a guess at, being close to the same between pre and post 1990 with possible a hair of an advantage to the later ones (though I have no evidence other than anecdotal to support this claim).
The outer axle seal on the 1990 and later axles uses the same one as the 80 series which is certainly superior to the older seals as the seal lips are capable of moving around more and sealing better due to movement of the shaft during steering, loading, and when other factors such as spindle bearings/bushings are slightly worn or the wheel bearings are have lost their preload (only to a point, though). The earlier seals are perfectly fine if you keep things up to date maintenance wise - which lots and lots of people do not do a good job of one age and wear add up.
The manual hubs are the same.
Spindles are effectively the same except that the electric locking hubs use ones that have circuits to power the hubs. The knuckles are different too - using a smaller version of the felt seal and retainer rings that 80 series uses.
The disc brake rotor is effectively the same, though it has a different part number.
The caliper is upgraded slightly to use two of the same sized (larger pistons) than the earlier ones, and you can swap the later calipers to the earlier knuckles with some backing plate trimming. This is common upgrade for lots of pre 1990 LCs.
Sorry, I didn't give all the details last time. There's more, but this is enough for now.
~John