A late observation to this thread. There are many photos on the Internet of Southern Pacific GS steam engines painted in black with the large "Southern Pacific" lettering on the tender.
Here is 4455 in black with large tender lettering:
http://3.bp.blogspot.com/__TkY...SHZCNA/s1600/gg1.jpg
(Note the absence of side skirting).
4447 in a classic pose with black and large "Southern Pacific" lettering near Carlsbad Caverns National Park in southern New Mexico:
http://www.railpictures.net/im.../3076.1356540977.jpg
(Note the absence of side skirting).
Kato made some N Gauge wartime black GS-4s (4431 and 4438) with the small "Southern Pacific Lines" lettering on the tender. 4431 and 4438 would have been among the first GS-4s delivered in 1941 just months before the attack on Pearl Harbor. They may have spent very little time in Daylight colors before being painted black so as not to attract the attention of carrier based enemy aircraft. The Kato black GS-4s show side skirting which was likely removed postwar for those GS-4s being transitioned to freight service with dieselization. Kato also produced 4450 in Daylight colors with the small "Southern Pacific Lines" on the tender.
Kato GS-4s:
http://www.katousa.com/N/GS-4/index.html
https://www.katousa.com/N/GS-4/126-0303.jpg
The MTH GS-4 (4444) has the larger Southern Pacific lettering on the all black tender while Lionel GS-2 no. 4415 and GS-4 4436 have the small "lines" lettering on Daylight tenders.
The MTH GS-4 also does not have side skirting:
http://www.mthtrains.com/content/20-3485-2
Lionel GS-2 4415:
http://lionelllc.files.wordpre...2/11/6-11420_gs2.jpg
Lionel GS-4 4436:
http://www.lionel.com/Products...neID=&CatalogId=
A prior MTH issue of a GS-2, 4413, also had large "Southern Pacific" lettering on a black tender and no side skirting while 4412 has small "Southern Pacific Lines" lettering on a Daylight tender.
MTH GS-2 4413:
http://www.mthtrains.com/content/20-3061-1
The catalog version of 4412 shows large "Southern Pacific" tender lettering but a photo of the actual model in a current eBay auction shows the model was actually produced with the small "Southern Pacific Lines" tender lettering.
http://www.mthtrains.com/content/20-3060-1
3rd Rail made wartime black GS-4 no. 4445 in black with the small "Southern Pacific Lines" lettering on the tender:
http://www.3rdrail.com/images/gs4-black.jpg
MTH currently offers 4449 in Daylight colors in large "Southern Pacific" and small "Southern Pacific Lines" tender lettering.
http://www.mthtrains.com/content/20-3484-1
http://www.mthtrains.com/content/20-3483-1
Lionel GS-2 no. 4412 in black has a medium-sized "Southern Pacific" lettering with side skirting. This locomotive may have looked better with the small "Southern Pacific Lines" lettering as in the Kato models.
http://www.cttrains.com/Lionel_Pictures/6-11419.jpg
With 4449 and 4450 being delivered in spring 1942 I would wonder if they started their careers in black paint. The only photos I have seen of either with the small "lines" tender lettering is from a recent repaint of 4449 following her restoration to operating condition. I plan to purchase the following book to gain some more photos of the final generation of Southern Pacific steam:
http://www.sphtsstore.org/serv...1940-dsh-1957/Detail
The cover photo shows another GS-4 (4443) in wartime paint with the large tender lettering (and no side skirting). Perhaps the black paint scheme survived for some time into the postwar era.
Accucraft made the GS-5 in Gauge One in live steam in Daylight colors with small "lines" lettering and in postwar black with large "Southern Pacific" lettering and no side skirting:
http://www.accucraft.com/modelc/AL97-005-C.htm
4458 was delivered in 1942 and is shown here in Daylight colors with the large "Southern Pacific" lettering:
http://abpr.railfan.net/august98/08-21-98/4lsb2.jpg
(Note the black headlight rings and engine number frames on the nose - 4449 was painted with the black headlight rings as a variation following reactivation).
If you want to model a wartime train, go for a black model with small "lines" tender lettering and side skirting. A prewar or early postwar train could see a GS locomotive with small tender lettering in Daylight colors. Later postwar trains would probably be led by GS-4s with large tender lettering or, if the GS remained in black paint, a GS without side skirting.