The Zoroark event will happen when you take it to Lostlorn Forest.
As I personally own all three of both the Japanese and the English Crown beasts (the former of which are in my B/W), I can say one thing about the authenticity of this Pokemon:
Everything appears fine except for one thing; the Rowap Berry cannot be obtained in Generation Five yet.
and he arrived in my game with the Rowap berry... good thing i did not trade him... they make hack now so hard to tell the diffrence from the real thing now :/
Looks perfectly legit to me. Crown Beast for sure. If you ever get a Pokemon in a Cherish Ball (the all red) and it says, "Faithful Encounter" on the Pokemon's stats, it's a Legit Event Pokemon.
It has a Rowap Berry because that's the berry it comes with when you download it from Gamestop in gen 4, I believe. Then, it was transferred to generation 5 and traded to you. Case closed, yes?