After not finding anything on the net directly related to 90's wheel markings, I have to assume the wheel with the larger hub was from a different model. Most likely a ZX9.
I would image that the sprocket carrier was also a larger diameter to fit the ZX9 hub. Maybe due to the HP increase, they sized it up a few mm. But as they say, assumption is the mother of all FU.I was looking at the parts fische for awhile, trying to figure out if another zx sprocket carrier hub could have been used. Only thing I found that looks similar is the 98-99 zx9r hub. But, I wouldn't have thought that those inner dimensions would have been smaller on a bigger CC bike.