If you notice in the game when you switch weapons, the HUD still uses the look of the old guns, in 2.2.1 they changed the shotgun and machine gun models, but never changed the images for the HUD. This isn't really a bug, but it's a little detail that a newb would be confused about.

Well, the developers knew this. But its not important The whole thing will be replaced by something different in the future anyways...