Bill, I go by the drawings:
http://www.vanpeltsales.com/FH_web/f...el_ID_1935.htm
http://www.vanpeltsales.com/FH_web/f...el_ID_1936.htm
usually BUT the British versions of the time [Model C then CX] differed in side louvre design, plus they imported some US chassis as well. However I am suggesting 1936 as the War Department acquired some 1936 Ford Pick-ups with US chassis. So it's an educated guess? I have similar problems with distinguishing 1939 versus 1940 Chevrolets....!!