I didn't use the gasket, I ordered one, never even looked at the 08 diff honestly, bought it and it's been sitting in the parts pile since. Thanks for the heads up though, I'll take a look at it this weekend.
The 08 cover works great. Used stainless hex cap screws and lock washers. No gasket, just use black rtv. Hasn't leaked a drop. I milled about an inch of a fin off at the bottom of the cover and drilled and tapped for my temp sensor.