Weird looking axel

So I got these two lightly used Ferraris off of eBay. They both look pretty good and as you can see in the pic below, the rivets are still in place so they've not been messed with. If you look at the side view of the black car and enlarge the Photo the end of the axles look very brassy. The photo does not really show how brassy they look in person. Is this common within the hot wheels world?

I'm gonna take it apart in a week or so and mod the hell out of it for the Lambo Ferrari drag race. So I will learn more at that time, but I am kind of wondering if this is a different type of axle.