If it is a true 14 day cruise...not two 7 days, B2B, it should have 3 Gala nights. If it is two 7 day B2B, it will have 4 Gala nights. Without having the itinerary in front of me, can't tell you what days Gala nights will be.
Again, if two 7 day cruises, the menus will repeat. If its a true 14 day (which you are hinting its not), you will 14 different menus.