Hi I have been on the legend of the seas and yes it had 2 sittings, but don't forget you can change this (if ships not too full) You can also eat in other places thay have available. hope this help.
Set dining times of around 6,15 and 8,30. There is a cafe called Windjammer on both ships. Navigator also has alternative dining venues called Chops and Portofinos [$25pp and $20pp supplement] and also an American Diner called Johnny Rockets $3.95pp suppl. Legend does not have these alternative venues.