I don't see anything wrong with repainting a body in bad condition
In good day , you can buy 3 cosmetically perfect original Leica bodies for 500 dollars in US. And you are not painting your old toyota but a Leica. If you have large stomach to paint a classic to black , I see something wrong with you.

Submariner , Navy , Air Force Leicas are the ones which painted and engraved FED 2s from Ukraine and Russia. They look cosmetically perfect and 120 dollars or cheaper at ebay with 30 day money back guarantee.

Money is yours , you can buy M series body for 500 dollars also or a R4 or Leicaflex body for 100 dollars and a 90 mm Elmar in the good day.

Japanese man is intelligent tourist trap , thats all.