I don’t know if it would be allowed (also don’t know why not). But I would spring for the LP tank hook up rather than use the pricey 1 lb disposable bottles. We did use a 2 burner Coleman last summer here in Socorro for Socorrofest to preheat up the BBQ (Used my big SS Dutch oven to bring water to a boil and set the cold BBQ in it using Reynolds Oven bags. Once hot, we turned the BBQ out into clean 1/3 pans and set pan in the steam table. I can’t really tell you if the local HD approved or not since our event “approval” consisted of “Hi, How’s it going?”
The only thing we use the 1 lb tanks for is our Coleman LP lantern (which we used for Socorrofest as well).