Hi Randy
There may be specific answers for certain years. I have a 1-ton 1946 panel truck and the sheet metal front fenders are the same as a 3/4 or 1/2 ton. The doors on the 1940-46 at the same on most all of them except the COE and panel truck/suburban which are quite different.
A great way to determine this is to use the reference parts books put out by GM for the era you are working on.
Brian
