In Australia, these 1942-1947 Ford Commercial Fords are commonly referred as "Jailbar" Fords. I don't know if they are called that in the USA? Regarding telling the different years apart, I can't talk for USA Ford, but our Australian 1942 models didn't have Quarter windows, as is evident in the above photos of this restored pair of 1942 Ford Trucks. They were entered in different local Ford shows a few years back. Don't know if this helps?