No, they didn't strip all the way down, but did get their jollies on by buzzing around shirtless (Harry) or just wearing underwear (Niall). Only, here's the thing. This video was captured on security cameras at the hotel, so it's kind of suckish to share it with the world on YouTube.
Fan reaction to the video is mixed. On one hand, Harry shirtless and Niall shirtless in his underwear. On the other? Invasion of privacy.