The hood emblem of a 60-61 Chevy truck will certainly have been copyrighted, and was probably trademarked too.
The copyright duration will be as specified in the 1909 act (see here) as amended by the 1976 act.That means it will last at least 28 years from first publication, but will have been capable of renewal in 1988 for another 47 years until 2035. (The starting point may have been earlier than 1960 because the original publication may have been earlier - but if they changed the design more than trivially, that change will have it's own copyright.)
Assuming Chevrolet's IP department are not completely brain-dead, they will have extended the copyright, so the ornament will definitely be copyrighted.
They have probably trademarked the symbol too - but how that affects will depend on what business areas they have trademarked it for, and what you want to use it for.
Final thought: Chevrolet have a bigger legal department than you do. Even if you eventually prevail in any lawsuit, you can be bankrupted by the legal fees.