All three prequel films will be screened in 3D at Celebration Anaheim, we hear from the Star Wars Insider via Yakface.
Although The Phantom Menace 3D went into wide release in February 2012, the remaining 3D releases were “postponed” in early 2013, not long after the Disney sale/Episode VII announcement. Attack of the Clones 3D was shown at Celebration Europe in July of that year, but this will be the first chance for the public to see Revenge.
The original trilogy screenings at Celebration Anaheim will be in standard 2D.