I've seen a couple sets of these in person, and there was a nice original GMC suburban at the Stovebolt Reunion a few years back. One would think that since 1963, and nearby years, are so "new" that SOMEONE would have the correct, definitive, answer!

1937 Chevy Pickup
In the Gallery
1952 Chevy Panel
In the Gallery
More photos
1950 Chevy Coupe
Pictures!

I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
I can explain it to you, but I can't understand it for you smile