The Milw did rebuild a series of wood cupola cabooses into bay window cabooses in the 30's. They were initially painted 'aluminum', but were repainted into the classic 'orange' rather fast. The aluminum was a failed idea to make them more visible at night.
They had the maroon 'Milwaukee Road' lettering just below the roof, and the road number on the bay window. The red logo did not appear until the mid 50's. I have never seen a picture on one of these cabooses in the late paint scheme(I did paint a Walthers kit in that scheme however!) The steel 'rib-side' cabooses were built starting in 1939, so would be appropriate for a mainline train in the 40's. There have been brass N scale rib sides and JnJ Trains has done a cast resin kit:
http://users.dwx.com/~jnjtrains/products_%20frame.htm
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
I might be getting into N scale steam and wanted to find the accurate type of Milwaukee Road caboose for this era (1940s steam period). I have seen some photos of old wood cabooses painted boxcar red but were Milwaukee's bay windows painted in the orange color by this time with a red Milwaukee herald?