Are Staff using Gluten-Free Brands of Prepared Items?

Are the brands of prepared sauces used in food preparation of "Gluten-Free" items known to be "Gluten-Free"? (i.e., Vinegar, Ketchup, Tomato Sauce, Jelly, Syrup, Yogurt, Sour Cream, and Peanut Butter etc.). (Why: Because even though the corporate recipe might call for a certain "Gluten-Free" brand of ketchup and mayonnaise used to make that Thousand Island Dressing, the Chef might have decided to use a different brand because it is less expensive -- and possibly Gluten-Contaminated.)