I have the tractor apart to repaint it. It seems as if it was Simplicity Orange after all. It doesn't appear to be a primer similar to the way David Bradley used a dark green primer. I have decided on Rustoleum Chevy Orange as the closest to paint underneath parts that were originally bolted together.
Surprisingly the gearcase had "virgin" grease after 62 years in the hollow of the idler gear. The gasket disintegrated so I plan on using a RTV as it is only grease and not oil in there.
The engine is in poor shape with the cracked mainfold allowing water into the head and is going to be a winter project. So in the meantime, I have a HF 6.5 hp engine to put on it so to be able to use it with a snowplow this winter. I know - Blasphemy!