I wonder if anybody knows the difference between these to earbuds? The first set is a first generation earbud with black covers. The part number is 603-2482. The second set is also a first generation earbud but with gray covers. Part number 603-0679. I have found both black and gray earbuds in both first and second generation iPod boxes? That is why I have to ask if anybody knows for real? I would guess a lower part number would suggest an earlier model??