ZJs came with 3 t'case choices: NP231 or NP242 part-time cases or NV249 full-time case.
ZJ trans *should* have the same bolt pattern as an AW4, since the ZJ guys talk about converting 249s to 231/242s, and it wouldn't make too much sense financially to produce different patterned transfer cases since YJ/XJ/ZJ/TJs all use common cases. However, I would definitely ask this question on NAGCA.com, since they cater to Grand Cherokees.
Edit: if all you have is 4hi (or Full-Time), N and 4lo, it is a NV249 t'case. Search on NAGCA for conversions.