[factorystock]

Welcome to the site, we can always use some more purists who appreciate the way they looked when new. You are right, there were two different 17" wheels, a 5" and a 6". Trucks that came originally with 7.00-17 had 5" rims and trucks that came originally with 7.50-17 had the 6" rims. IMO, the black rims and the green rims are the same. Pre '60 trucks and '60-'68 step vans with solid front axles came with a flatter design 17" wheel. The look is pretty obvious, the center section does not cone out as much as the wheels in both photos. There should be markings on the back side of the wheel which indicate year made and size. The 17" was the heaviest duty single wheel offered by GM and it looks it! The blue C20 in photo has the 17" wheel. They were all black. 16" wheels were black also, but had a silver ring. U.S and Canadian Chevy wheels would be painted the same. GMC's built in Canada had different paint rules on wheels, and yes, wheels were painted body color on Canadian GMC's for solid paint, not sure on tu tone paint jobs.