BlackTomC,
Are you going with clear coat for looks and/or just some extra protection?
The paint itself should protect the molding I think. The ones I have now must be OEM, they are look to be without CC.. they aren't as shiny as, say, the outside body of the vehicle.
How would rust even get down in there anyway.. unless people were holding onto the door ledge and over 30yrs they presses on microscopic, abrasive dust particle down in the crevices and wore off some of the paint. Oh well, one of the mysteries of the universe and I'm just frustrated with having to paint what is a already in good condition piece. lol.