No, it isn't, just as it wasn't enough to prove it when they skated out in them two years ago. Just having the players wear those jerseys once does not delineate that those are the "official" jerseys versus the "throwback" jerseys. Again, that's all I'm saying...they'll likely say something after the game to confirm/deny if they do skate out in throwback style jerseys, but until then it could simply be players wearing throwbacks...
Unless of course I'm missing something with respect to the NHL rules on throw-backs...