As I recall, all of the r200 diffs are the same. If there are any differences at all with the actually r/p chunk, it is as MMiskoe stated, in the ring gear bolt size.
The main differences are in the stub axles. There are five bolt and six bolt versions. The 6 bolt flange came on the 240sxs. The five bolt flanges came on various other models and some infinitis that also use the r200 rear end. Both stub axle inserts are I believe 23 (or 24) splined. But of course we can only use the one that came on the 240 (six bolt flange).