Pre-release private party

I’d like to know if private events participants are eligibile to open next expansion packs in advance. Me and my friends are setting up a private fireside gathering on the 4th of August, and we would like to know if we will be able to open Uldum packs in advance during the event. AFAIK during the pre-release period of Rise of Shadows people used to be able to open packs and use the cards to make decks to play locally in unlisted (private) gatherings. Does anybody know if we will be able to the same from the 2nd to the 5th of august (Uldum’s pre-release time frame)?