They do not fry anything containing gluten.
I am a sensitive celiac and very cautious about where I eat. I have ordered the cheeseburger squared lettuce wrapped and french fries probably more than 25 times without any issue at all! They do not fry anything containing gluten in their fryers. They do have UDI's buns as well---get them untoasted.
— Somewhat
— Gluten-free items are marked on the main menu
— Most/All
— Excellent