[60-66]

From what I have seen on original low mile trucks is the 1966 models were the only ones with Chrome sill plates from the factory. All other years 1960-1965 were cad plated silver. The chrome sill plates are or were the only ones available after a certain time early and are the most used for replacement parts. Paint under the hood on many things depends on Chevy or GMC. Chevy had glossy radiators and air cleaners like GMC. But, GMC used a more glossy paint on inner fenders etc. than Chevy did. The gloss however was not pure gloss but was more semi gloss if that makes sense ? I see many over done finishes under the hood on restorations. Edit : In March of 1966 the silver cad sill plates 3763219 were discontinued and replaced by the 3882418 chrome that was used for 1966 production.