I don't believe that the 16 gig one is rare at all... It just either A: Isn't supposed to have it. Or B: Got rubbed off.
Otherwise... I would just check eBay to check the value of them. Just search for the different items in the recently completed section in eBay. :y:
Thanks i'll have a go on ebay, and This 16gb came directly from apple, because my other 16gb got damaged, the previous one had 16gb labeled on it, this one however was shipped without 16gb, so i thought it was rare