Still they have at least stated that dedicated servers will be shipped with the game so the only real questions are in what format i.e. ranked etc and will the files be made public?
I honestly don't see cod moving to a central server stats system like Battlefield. It costs money to upkeep that sort of system. That's why I think cod has been using client side stats storage since CoD4. It's also pointless to keep ranked files from the public if the stats are stored on the client thus allowing stats modification applications to be used.