Maybe he would be just like you up to the point the copy was made, after that you'd have different experiences (even if it is by having a different perspective of the world), and maybe that's enough to have the sense of his own identify?
Maybe you'd be the same in a fraction of an instance in time?
Maybe you'd never be the same because the process of duplication is an experience within itself enough to develop a different self?
Who knows :D
I know that's impossible for many reasons, but which body would you wake up in if somebody would make an exact subatomic-perfect duplicate of your body. Wouldn't the copy become just a twin having identical memories and believing he's you? Wouldn't you still only see the world from the point where you've been rather than where your copy has emerged?