I'm pretty sure that the truck 6 lug wheels (15s & 16s) with spring clips will accept just about every truck & car hub cap back to late 30s. The passenger cars stayed with 6 lug rims until 49 when the car only went to 5 lugs. I remember how surprised I was when I learned that my 47 coupe hub caps also fit on my 57 half ton pickup wheels.
The great thing about GM is that so many parts will bolt on for many years running. Like my 46 pickup with a 1961 motor bolted to the 46 bell housing, 57 pickup hubs/brakes bolt on my front axle, this list goes on and is probably listed someplace on the Stovebolt site.
