Is there any difference between the SuperDrives of different years of MBP, in terms of which caddy will fit which laptop? Based on info from mcetech.com all unibody machines use the same caddy, but they do have a separate entry for the pre-unibody MBP. I want to get two of those, one for an early 2008 pre-unibody 15" MBP and one for a 2009 13" MBP. Looking at something like this: http://www.ebay.ca/itm/Universal-Ne...7?pt=US_Drive_Bay_Caddies&hash=item3378a65c67 I'm not quite sure if it will work with my older laptop. Anybody used these in pre-unibody laptops?