Their truck is definitely NOT GF (anymore?). I just waited in a long line after reading the other review here, and the truck workers just confirmed that all of their sushi is marinated and they do not use tamari. There were no GF options available.
Menu is marked with gluten free items. Some of the default sides have gluten, but the staff is always happy to change sides. Only GF poke I’ve found in Seattle, so it’s always a favorite!