pot_luck, the "teeth" part on the zipper appears to be brass color. I would never have noticed that unless you asked. It is odd that the pulley is silver and the teeth are brass, but it's not noticeable to me. I am looking at the bag right now. It's 9pm and my lighting isn't the best. Maybe it would be more noticeable if the bag was black? I'm not sure. Also, since the top part slouches over, you cannot really see the "teeth" when you are carrying the bag or even putting it down.
Are you concerned about that?