It might well be in 1941 this photo was captured. But it must be after february.
The first GMC CCKW was manufactured this month. And take that it had to be transported over the atlantic give it another month or two at least.
The CCKWX was last manufactured on february 1. 1941 with the serialnumber 13188 and WD number W-428589. And this was one off prototype (L1) that was a tipper without winch (short wheelbase).
And on the photo it also clearly shows that the axles are of the GM Banjo type. This was never used on the CCKWX trucks, they all had the Timken split type (as did the ACKWX-353).
The cab in the background is of the Model 1609 since it has the hole in the roof. The type of cab used on the CCKWX was the Model 1574 superseeded by the Model 1608 (without the hole in the roof). This was done at the same time as the "configuration changed from CCKWX to CCKW and at this time they also started to use 352 and 353 differing the long wheelbased GMC and the short wheelbased. Before ferburay 1. 1941 when they used the suffix CCKWX all GMC was designated 353 (also the short wheelbased ones).
The cab Model 1574 and the following closed types (Model 1608 and 1609) are almost similary at the outside. They differed inside.
The Model 1574 had an ashtray as one feature that did dissapere. And as you konw, the Model 1574 was a militarised civilian cab as used on the ACKWX-353 (but on this model sporting the civilian front too, and the fueltank inside the cab).
Well this was just some quick words from my head just before I am off to get my beuty sleep.... and I need a lot
Rolf
PS: It will be a series of articles on the GMC in the english edition of Mud & Snow next Year...