Actually the Mountain type has no prototype. The boiler is bronze sand cast, and the rest is just parts from elsewhere. As far as I can tell, Southern had no oil burners. I put oxide red on cab roofs of most of my locomotives..
I have the skill to put as much detail as I want on my models, and often stop short of full and accurate detail. The Elesco feed water heater is what demands all those pipes on the PS-4. My point was if you get to the point where a cab roof color is the make or break decision point, you are getting close to demanding accurate models in size and configuration - and I regard that as a good thing.
