I'm going to replace a couple of stuck valves on a gas cooktop. Looks like
they just screw into the manifold once the ignitor switches & wiring
harness is removed and the manifold is lifted enough to provide rotating
clearance.

The threaded connection is a continuation of the valve body which appears
to be aluminum. Threads are pretty fine. Is this an application for
Teflon tape, pipe dope, or nothing at all?