I would bring it to the dealer. I am sure they will say everything rusts eventually but not in 3 months.
I had the same thing happen to my lugs (See here: http://www.ramforumz.com/showthread.php?t=169320
) I bought from Discount Tire. They didn't even make it a whole winter. They gave me the option of the same or painted black for free or stainless if I pay the difference. I went with black. Hopefully your dealer will be as good if not better.