Absolutely lovely work, Przemo, your painting skills are a source of constant wonder.
Regarding the camera, I think we can safely assume that if the instructions called for those colo(u)rs, it's because somewhere in a climate-controlled warehouse belonging to Peter Jackson, there are a half-dozen originals sitting on a shelf that the WnW team had to use for reference. Richie W posted a photo of the Type C a few months ago in his epic BE.2 build:

Slightly more red finish, maybe, which would photograph on orthochromatic film as looking very dark like the ones Spyros posted. So maybe both interpretations are right...?

Dutch