I went to this location and had a few chips with salsa and a single fajita and had a reaction. I would guess they do not have separate cooking areas. After reading the other reviews and the staff saying everything was gluten free (except for a few items) I thought it would be safe, but unfortunately was wrong. My sisters also have Celiac and both had reactions. If you have celiac I would sadly recommend finding somewhere else to eat.
We ate at the Park / Plano location of Blue Goose Cantina last week; it was my first Mexican restaurant since my diagnosis. (Sadly, the two Mexican restaurants that I ate at before both have zero knowledge regarding gluten-free options.). I first called and verified that their Queso, salsa and chips were GF. I ordered cheese and beef enchiladas with Queso, rice and black beans. I also ate chips and salsa. It was all delicious with zero symptoms.
Waitress told me the vegetarian menu was the same as the gluten free menu.