I know we have been down this road way too many times, but I can verify that on two existing cars, NP 91366 (Built 1949) at the Northwest Railway Museum, and the one owned by NP historian Rick Leach (I think was built in 1954), that the area that is protected from light by the door is yellow. In fact NP drawings list it as Chrome Yellow. It does have a slight cast towards the orangish side but it is a yellow.

Rick has been working on matching various NP paint colors from actual sources.

Richard Wilkens