I finally found a set of the OEM 8x16 forged alloy rims for my 2001 2500 4x4, but they didn't come with the matching center caps. Websites have a selection of center caps, but require the part number printed in the cap. Would someone please pop-off a cap and give me the part number? Also are the dealer-supplied lug nuts necessary to ensure the center caps fit properly? Thanks in advance.