I'm not much help on your questions but thought I might add something about the design.
I believe there were some early 47's that were really 46's so its possible to have a "Art Deco" looking truck but vin'd as an Advance Design.... but that doesn't explain a 46 being a 1948.

Hmmm, maybe some hanky panky on the numbers over the past 62 years or so??


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