Ultra grey, I use permatex moto seal. great stuff.

The cometic seem to be covered with graphite powder those would be used dry. I never tried sealant on those. Other gaskets and mating surfaces a light coat of spray gasket on each surface, wait a bit till it gets tacky, then assemble. The parts are shiny clean with Scotch Brite pad or 400 grit and cleaned with solvent. Or like the previous post dry is ok too. But needs to be clean and dry.