I saw this video and I was wondering if it was real, because it looks fake, but I still don't know
Fake. NuffSaid. Rayquaza cannot be caught in B/W without PokeTransfer or trade. Or from the Event in Japan.
It's fake, there is no way to catch Rayquaza in the game.Unless like usual you get it from trade or migration from generation-4 games.
Source: I tried this, with bad results.