Hi there, Quick question. I just got my iphone 4 delivered today and am intending to sell it for a quick profit. the buyer seems to be interested in my IMEI which he claims will tell him whether the phone is unlocked or not. i told him there won't be an IMEI on my invoice but there would be a serial number instead on the box and on the invoice, for which he seems satisfied as well. does the IMEI or the serial number tell you this information? thanks!