For 3.08 gears, you will need to find a good used set. There are plenty out there. I don't believe they make any new gears for 8.2 BOP's lower than 3.55 or maybe 3.36. The part of the rear that is gear ratio dependent is the carrier, which is the part that the ring gear bolts to. There are different carriers. I found this breakdown for carriers when I googled: 8.2″ BOP 2.76 & down / 2.94 to 3.23 / 3.31 (3.36?) & up. Maybe just find a 3.08 BOP rear and use the gears and carrier. Open rear ends are pretty plentiful and cheap and the internals are pretty interchangeable for many years of pontiac/olds/buick 8.2's. If you are looking for a good condition limited slip (Safe-T-trac) that could be a harder and more expensive find. They only make aftermarket posi carriers for 3.36 and higher.

The term "10 bolt" refers to how many bolts in the cover.