Maine Central Number Boards

I've noticed that most of the GP38's originally had black number boards and were later changed to white, was this the case for all the GP38's? On the same token, I've only seen picture of the GE's supporting white number boards; were they delivered with white number boards or were they switch out too?

Yes, the GP38s were delivered from EMD with black number boards. MEC replaced them with white number boards when they were rebuilt in the late '70s/early '80s.

The U18Bs were delivered from GE with white number boards and never had black number boards.