Looking at the description posted along with it at SWShop.com, it looks like it indeed has a removable helmet, which is nice. Here's what it tells us:
"Hasbro has truly outdone itself with the release of their Special Edition 500th Star Wars figure, Darth Vader in Meditation Chamber. Designed with incredible detail and superior articulation, the inspired package design allows for a lever on the back to be raised to lift off Vader's helmet! The packaging actually includes some of the design features of the chamber itself, so collectors might want to grab two of these--one for show and one for play. Celebrate the return of Vader in Revenge of the Sith with this amazing milestone figure available from StarWarsShop.com today! Limit two per customer."