check the VIN plate on the cut, if it's another E58-474 its a 4 pinion open diff.
Most of the ae92 MAP GZE's I've seen have the -474 boxes, with the earlier AFM ones having another open box... if the last digit is even, it's open. If the last digit is odd, or a "C" then it's LSD. The E58-115 and E58-11C are both LSD from what I've seen.