"On the return trip, the trucks were not empty. Salvaged shell casings, war debris of all kinds, wounded soldiers, POWs, and the remains of the dead were all carried back from the front to rear areas for processing."
If you're willing to adjust your time line, there are photos of CCKWs transporting German POWs to the Manteuffel Barracks at Strasbourg after the battles in Alsace in Feb 1945. One of the bumper codes in a photo in Boniface's CCKW book is 1A 54G 3354 113. There are other photos in the book as well, but they don't show bumper codes, though they probably are also 1st Army since they are delivering prisoners to Strasbourg.