There's a high-temperature powder coat available which I use in flat dark charcoal for all exhaust system components, including mufflers. It is far superior to any of the spray on or brush on alternatives. (Make sure your powder coat source knows to plug the ends of the muffler before blasting it in preparation for the powder coating or you will be in for a messy surprise on engine start up.)
There are several types of car shows..
If you are thinking about EFV8 Club sanctioned events then the car has to be as Ford built it..
The exhaust manifolds would have to be bare cast iron. The rest of the exhaust system would have to be bare metal.
The more casual type of car show, ie; street rods etc., anything goes, it's whatever floats your boat.
Sorry, but numerous Ford archives photos show painted exhaust systems on the assembly line (as well as those which are obviously not painted). A well-informed judge will know that.
Sorry, but numerous Ford archives photos show painted exhaust systems on the assembly line (as well as those which are obviously not painted). A well-informed judge will know that.