I learned that the US was able to build a lot of planes, tanks, and other vehicles necessary for war by converting existing factories. Those factories presumably built cars/trucks before the conversion. As a result were there any cars that skipped from say '42 to '46 model years (they weren't made from '43-'45) because they couldn't be produced in those factories?
Basically, yes. The factories were turned over to war production so there wasn't any capacity left.
Domestic automobile production ceased entirely from 1942-1945. So the answer is: basically everything skipped from 1941 to 1946 models.