Lou, I used to watch the Grand Canyon make its station stop at Fullerton, fairly frequently, in 1956-1960, and then less frequently until it was discontinued. The only thing I remember observing, hung on the scissor gate of the last car, was a non-oscillating red light.
Normally, the last car was a Valley series 6 section 6 roomette 4 bedroom Pullman. Those were the smooth side Pullman Standard cars, painted two-tone grey, and later solid grey.
I rode the Grand Canyon in 1952, as a boy, and there was no observation car. The last one assigned (heavyweight) was in the late 1940's.
I would suggest that you buy a CD of Fred Frailey's Santa Fe Passenger Train Consists from the Santa Fe Railway Historical and Modeling Society. It is not expensive, and is a good reference for those who model Santa Fe. (Bold text not shouting, just thought it might get the attention of someone scanning the thread who might find the Society's books interesting and/or useful.) 
