It is quite possible to prove, but it is unlikely that anyone will be able to do it.

On what basis you'll term someone to be Satoshi. Anyone with the name Satoshi can't be real Satoshi, even if real Satoshi comes it is hard to confirm him to be the right person. Maybe with his official conversation and the forum account getting active we can conclude. Here too there needs to be someone who is close to him or had some face to face business with which the identity can be confirmed. In simple looking for Satoshi and thinking whether his identity gets revealed is unnecessary.