OK... now you are getting into trademark law. Yes, Chevrolet (General Motors) owns the trademarks to some designs, however, you also have to look at how they are used, and if the trademarks were renewed. Then there is the R inside of a circle, that indicated that it is a registered trademark. In the case above, we are talking about who owns the artwork that he paid to have done. In this case, it is my opinion that the person paying for the artists work owns the products of that work. That doesn't mean that as own of that work, you have complete and unfettered use of the work. My guess is that Chevrolet in all probability still owns the trademarks on the designs, but isn't going to come to his garage and demand a royalty for the use of said trademark. If he were to make a bunch of them and attempt to sell them, then he would be violating the trademark, however, for his own personal one time use, he wouldn't be hassled by the owner of the copyright, trademark, or any thing else. Most of the items that have a GM trademark on them that is for sale is a licensed product, such as reproduced emblems.