Your hand drawn picture in the first post is not correct. All 3 years have the same belt line with the top one thin and bottom a bit thicker. Look through the Gallery and although it is often difficult to tell from the pictures, I think you would see they are the same. My 37 and a late 36 parts cab both had the thin and thick belt lines. From your picture I don't think we are going to be able to tell what year that truck is.
Kent

Last edited by Lightholder's Dad; 01/31/2021 12:14 AM.

1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix