Strange '73 1ton question(s)

[fourspeedwagon]

I have a 1973 1 ton dually that has a boxy cabover type body and a flatbed. The grill say Chevalier- my guess was some kind of Canadian contraption originally? My current question is about the rims. It has 16.5 inch rims with the big "rings". I was under the impression that a 73 wouldn't have these wheels. So then I started wondering if it is really a 72 that took a little time with the custom cab.
Any thoughts on the name, the wheels or a good way for me to identify the real model year would be great. Thanks! Greg