I've been looking around for info on this for a while. Unfortunately I don't have a row of engines to pull apart and check for myself.
It seems that the only difference between GE and GZE of a given year is pistons, rings and cam covers. Everything else is identical (bar accessories like alternator, SC etc etc).
So while I haven't done it, I think the 4AGE rebuild kit would do a ZE fine. As long as the kit was for the correct year.