Way back when flying was dangerous and sex was safe, MMAs DC-3s were all metal, POLISHED finish(good old dura-glint, done by hand) to so called save weight, some 100kg was I think the figure and they went well when polished.
A photo in "I flew for MMA" shows a group in reflection under the wing very clearly.
If you have a repair, paint can hide all sorts of things.
