3.4L thermostat housing gasket?

[Solaris]

I have a remanufactured engine and the thermostat housing has a gasket installed. I've been to 2 parts stores and a Pontiac dealer, all saying you just use the rubber thermostat ring, no other gasket. My Chilton manual even shows that "some applications" may not have a gasket, but doesn't specify which. Does anybody know for certain what that housing requires?

[FunkZ]

There was no gasket on my 3.4 when I replaced mine, and the new thermo did not come with a gasket. It is the 3.8 that has the gasket.

[Solaris]

Thanks. Coolant leaks out when I loosen one of the bolts on the housing (with the radiator cap off), so I have to assume there is no rubber ring installed now. I'll soon find out.