As an addition the post above here's the photo from 1951 of the Golden State headed by a GS4 in Daylight paint. You can see the red a silver Golden State cars after the two baggage cars behind the locomotive. I've been running my GS4 with the Golden State based on this prototype photo, as it happened at least once.
Does anyone have any pictures of a black GS2/3/4/5/6 in freight service they can post?