Hy 1936only, in my reference book GMC The First 100 Years, I could find no mention of C.O,E, trucks until 1937, however in one of my other reference books, GM The First 75 Years of Transportation Products, there are references to a 1934 T75 tanker and a 1936 F-61C. It must be remembered that GMC built trucks far in excess of the capacities of their Chevrolet cousins. I believe it is accepted that in 1937 GMC began producing cabover trucks that would compete size for size with their Chevrolet cousins, however they were alone in that market until 1939 when Chevrolet started to produce their own cabover trucks, hope that helps.
