A morning questions after looking at the recommended threads.

Is the fuel tank "356 engine gray"? My car has undercoat in the trunk, and passenger compartment (see pictures above), should those areas be smooth chassis black (satin)? I first thought of just painting the areas but then I thought about the installation of the coverings and figure that it all must go. I assume that the undercoating is correct in the fender wells and the underside.