I just bought a 2004 350Z from an individual. She was the second owner. The car only had 6300 miles and is in excellent condition. I noticed that all the wheels have a blue dot of paint on them about a 1/4" in size. The paint looks like it is some kind of very hard enamel paint, almost like a fingernail polish, that will be difficult to get off. Would this paint be some kind of marker on the wheel? Has anyone seen this before?