On a folder, almost the full light path is bellows. Not like, say, a TLR where the chamber between back of lens and film is a metal chamber.
Areas outside of the light path and film gate will have minimal reflection issues. Often areas like the film chamber have a darkened metal surface under the paint- bluing or such?
More than reflections, I'd be concerned about flaking paint. Every time you open and close a folder you create vacuums and wind currents. This will stir up any particles, and living in a universe ruled by Murphy these particles will find their way into skies, causing black dots and loads of fun with retouching.
So whatever you do with the existing paint and repainting, make certain that paint isn't flaking off.