Beautiful cars! Thanks to all for the photos.
With regard to the GS number boards, actually, it seems that there are multiple photos with the GS forward indicator boards as late as 1946, although there may be exceptions. That is why most people seem to associate that change with the SP Lines/"Southern Pacific" lettering change in 1946.
For example, from a lengthy discussion of the prototype GS-4 (and specifically 4449) in another forum:
Note; this is all based on photos of other locomotives. The book Southern Pacific Passenger Trains Vol 2 has numerous photos of the locos before and after the war. And all of the photos dated 1946 or later show the train number board moved to a more central location. Some of these photos show the same loco with the number board up front before 1946 and moved toward the back after 1946 (proving that existing locos were altered). I have not found any photos showing the 4449 either way. Photos of sisters 4448 and 4452 show the post-war change. Thus I am inferring that the 4449 was not an exception and was also changed. Since the number boards on the 4449 are now on the front again, I assume the number boards were returned to their original location (at the front) at some point. My guess being that this was done when it was restored for service on the American Freedom Train circa 1976.
The train indicator number boards were originally, i.s. "as delivered" in the forward position (from about 1936 through 1941). When the first GS-4 locomotives were delivered in 1940/1941, the station agents and train order station operators began increasing their complaints about not being able to see/read the Train Number Indicators because of the bright headlight plus compounded by the bright Mars Oscillating light on the GS-4 locomotives. As a result, the Mechanical Dept. began relocating the Train Number Indicators, as well as changing the mounting angle, in order for better visibility from trackside.
When 4449 was removed from the park displaying 1974, for restoration and subsequent use on the American Freedom Train, she was restored to her "as delivered" appearance, i.e. with the Train Number Indicators moved back to the forward location.
When the AFT was concluded, and 4449 was returned to the city of Portland, OR, she was placed in indoor storage, until 1979/1980, at which point she was re-painted back to the post-1946 red, black and orange Daylight styling, which included the large "billboard" SOUTHERN PACIFIC lettering on the tender side, and the relocation of the Train Number Indicators to the approximate middle of the skyline casing, in preparation for her "new career" of excursion service with attendance at the California State RR Museum grand opening in May 1981. SP4449 remained in that post 1946 configuration until about 2001, at which time she was repainted again, back to her red, white and blue American Freedom Train styling as part of the 25th anniversary of the AFT.
Somewhere in all this, she was also repainted black for the BN Employee Appreciation Special. Finally, in the Mid-2000s, 4449 was repainted back to the famous Daylight colors of red, black and orange, but in her original "as delivered" (1941) configuration with the Train Number Indicators moved forward and the small "Southern Pacific Lines" lettering high up on the sides of the tender, which she still retains today.
