Wrong.
Wrong, wrong wrong!
Stainless steel will corrode. Not as fast as with Cu and Alu, but it will still corrode:
http://www.pemnet.com/design_information/galvanic.html
If you attempt to coat a metalic res, you have to make absolutely sure that it is covered, because the smallest hole in the coating will cause accelerated corrosion, as that one little spot will corrode "on behalf" of the entire res.