They may not have gf bums, but when you say you have an allergy to gluten, they cook it on a clean grill with clean utensils. I usually remind them to put any burgers with a bun in it's own bag away from my protein style and fries since they only partially wrap them.
When they had only been open a couple of months, I did have one young woman tell me that, "None of the buns are wheat; their all white buns." I couldn't even speak for a minute. I emailed corporate from the website and they assured me the whole shift would be retrained on allergen protocols.