It is probably a moot point since neither could be anymore then the #3 until Brodeur retires, and then neither more then a #2 until Luongo retires. Still even if you are a #3 you get the medal, and get to practice with the team, and experience it all except competition of course(barring injuries).
I wouldn't be so sure that Luongo is a lock. He still has quite a bit to prove when the games start to mean something. If he can get to the playoffs this year with Vancouver and make noise, then I would hitch my wagon to him in terms of being a Team Canada starter after Broduer, but i'll have to see it done when the games matter.