http://www.gmheritagecenter.com/doc...hevrolet-Trucks/1946-Chevrolet-Truck.pdf

p 49 on serial numbers explains your question. (scroll down 7 pages)

DO = regular Muncie on 3100.

21911 is production number. Numbers started at 1001 at each plant.


"Nothing astonishes men so much as common sense and plain dealing." - Ralph Waldo Emerson