Regarding the supercharger base gasket for the '93, it'* GM #24507608, and I've never found a local parts store that carried it.
It costs roughly $12 at the dealer. If you can't find the gasket at a local parts store, call more than 1 dealer, and ask the closest dealer to match the lowest priced dealer (my closest dealer quoted roughly $20 for the gasket but matched the other dealer'* $12 price).
You don't need sealant when installing that gasket; it comes with a bead of sealant already applied. There'* also a nylon "pin" installed in the gasket near the snout end (passenger side) that keeps the gasket in place and helps ensure that you install it correctly.
By the way, note in the photo (in the previous post) that the o-rings weren't installed in the 2 coolant passages (the o-rings are yellow). If yours are in bad shape, you'll need to buy those 2 o-rings also.
'99 Bonneville SLE, white, 112,000 miles
'02 Park Avenue Ultra, white diamond pearl, 88,000 miles