diff in '98 Z28 - Torsen or Auburn

Before I go through the expense of opening up the diff, does anyone know for sure what came on the '98 Z28s?

I was told by Sm Strano that it is an Auburn (last year for the Auburns) and that was backed up by someone else in the 'future vehicle news' forum who posted a GM media guide for '99.

But...Red Planet posted that the '98s were the first to get the Torsen.

So...does anyone know for sure?

The 98's came with Auburns, with the Torsen being optional. Actually, you could get the Torsen as early as 97 if you had an SS.