I know 15 inch artillery wheels were an option for 39-46 GMC 1/2 ton trucks and I believe they were for Chevy as well. 16 inch wheels are 4 1/2 inches wide and the 15 inch are 5 1/2 wide. It's more common to see the 16 inch artillery wheels on earlier trucks. 16 inch artillery wheels were standard equipment on 1936 GMC 1/2 ton and may have been an option for Chevy.