Au contrare, the animation would disappear.
The special entrance would not trigger when N's Pokemon are used in Black and White due to the entrance not being in the game in B/W. They would be just like any other Pokemon.
However, if traded back to Black 2/White 2, then the Pokemon's entrance would go off. This is similar to a Shiny Pokemon from Generation 2 being transferred to Generation 1, then back again.
Source: Having N's Purrloin in White.