FAQ for
Anchorman: The Legend of Ron Burgundy (2004) More at IMDbPro »

I *think* the answer is yes. In an interview on Fresh Air with Terry Gross, Terry talks with the filmmaker, and he says that he wanted the four men to learn a song with four-part harmony, and he chose Afternoon Delight.

There is also a deleted scene where Will Ferrell starts singing and has to stop, and he does not appear to be lip-synching.

IMDb has Anchorman 2 listed for release in 2010.

The Unrated version features a cut that's approx. three and a half minutes longer than the theatrical version of this movie. Nearly all scenes are extended plot sequences that are of more or less value for the movie itself. Nothing really spectacular but a detailed comparison between both versions with pictures can be found here nevertheless.