We did the galley tour on our March 5 7n cruise on the Fantasy. I don't know if they are available on all cruises or not. It is a ticketed event, so you need to see GS when you board and ask for tickets. On our cruise, there were only 2 tours offerred, both on Thursday afternoon, I believe
To be honest, I was a little disappointed in the galley tour. There were probably 15 people in our group and it was very hard to hear the chef who was walking us through. He didn't know any of the interesting "facts" I thought we would hear (like how many # of potatoes do you go through on a cruise...etc.) He really just walked us in a circle around the outside perimeter of the galley and talked about the different prep areas. I was actually pretty surprised that there wasn't more pre-prep going on when we toured (2:45 in the afternoon)....we only saw one guy working on putting together some dessert cups. One interesting fact he DID tell us was that there are actually several galleys:
Palo
Remy
Crew
One for the poolside eateries
AP/RP combined
EG
seems like there were 1 or 2 more, but I can't remember