It is a shame as the corrosion on them does look to be pretty bad.
The potential end results are down to the achievable surface finish on the steel depending how bad the flaking/pitting is as Tim says, and has little to do with the actual quality of the metal.
Whereas the surface finish will dictate the end result for painting and especially when electro-plating, those old doors and frames weren’t generally electro-plated, painted or lacquered like the safes, and they usually got extra special ‘finish attention’ so that ‘what you see’ really is ‘what you get’.
If the intentions are for static display only, then that should make things far easier for you, and lend more options, as they could be blasted/ground etc and then lacquered, or painted, but that’s if they don’t need to be operational, ie the doors not being forced tightly into the frames by the pressure/clenching mechanisms, the action of which will abrade applied paints or finishes.
I guess you’re not really going to know properly until you get stuck in and establish just how bad that corrosion is.
