exactly. z32's are all star shaped.
so are cefiros, q45s, and other certain beasts.
generally if they were 6+ cylinder powered, they were 5 bolt powered. however earlier z31s are 4 bolt. (and they are 4 HUGE bolts)
some skylines are 6 bolt however, depends .. its wierd.

stick to a six bolt and you'll be fine.
however you can get a 5 bolts, you just need to swap output shafts.
best bet is to post and ask if its a good diff. and we will tell you what will need to be done to make it work, since you obviously can't read any faq's yourself on it.