In case you missed it, the Offical Site confirmed several Episode II rumors of late, including Holocrons:
Plus, more than 500 images grace these beautiful pages -- including models made specially for the Visual Dictionary: concept sculptor Robert Barnes has created stone mites and a duracrete slug; model maker Don Bies has devised two Jedi Holocrons and a pyramidal Sith Holocron; and ILM model maker John Goodson has cut away a clone trooper rifle to reveal its inner-workings.
So are they just referenced in the movie? It would appear so, since in the paragraph above in context it is talking about models made just for the new book they are advertising. At the very least though, they are mentioned in the film. Thanks to Starkiller and others for noticing!
Rebelscum Breast Cancer Awareness Charity Patch Posted By Philip on November 25, 2014: Thanks to everybody that ordered patches. I sent a check for $1,600.00 to the National Breast Cancer Foundation on Monday. While it's not as much as I hoped for, it's still very much appreciated. They will remain for sale in the store for anybody that still wishes to purchase them. Details after the jump.