Re: Question about original hardware
I believe that black porcelain and "bennington" (brown-marbled) knobs predate the white ones. Darker knobs were initially deemed more elegant because the blended in better with dark decorating schemes and dark-colored woodwork. By the 1890's we start to see ad marketing with the term "sanitary" valued as a sign of good housekeeping, along with it a lot of white surfaces in areas where cleanliness was desirable, like white bathroom fixtures and tiled surfaces, and whitewashed walls in kitchens. Particular types of doorknobs were marketed as hygienic, as germ theory of disease entered the scene competing with the prevalent "miasma" theory (bad air causing illness) but both theories were popular until education caught up with science.
Black-painted metal knobs remained the choice for service areas through the 30's I think simply because they were the cheapest alternative.
Remove not the ancient landmark, which your fathers have set.