I reached out to RC about the BOGO for our cruise next month also - this is their reply on what is covered:
A BOGO 2 Night Dining Package can be used all reservable specialty dining restaurant for dinner on the first and second night of your sailing. However, these packages do not include premium experiences such as Chefs Table, Mystery Theater Dinner, Wine Pairing Menus, Izumi Hibachi and up charges for special food selections. As a note, some specialty dining locations have a la carte pricing and so guests with a package will get a $35 credit towards the food portion. Any cost in addition of that credit will be charged at our normal a la carte rate.