i have two exact same 17 inch MBPs i am thinking on selling one , one has a lot of stickers and marks on it and the data on that is not at all important (i can format the hard drive no problem). the other one body has very clean and data on that is important lots and lots of photos and videos . i want to sell the one which has clean body so i can get better $ for it. it is possible to just swap hard drives between these two identical MBPs and sell ? would that make any different in performance and also the serial number on ABOUT THIS MAC is that written on hard drive or some place else?