Do I need a Gas Grill Liner?

Hi Everyone, General question I hope someone can help me with within the community. I'm currently building an outdoor kitchen made out of concrete block with granite countertops. It will be stuccoed so all concrete. I'm going to install a Napoleon propane built in + a Napoleon power burner. Do I need liners for these? Only reason I ask is I'm sure the builder may use some 2"x4" wood to create the final frame of the items to sit in on the concrete. But as the majority of the build is concrete I'm thinking it may not be necessary to have liners? If anyone can let me know their thoughts on this & give me a steer, I'd very much appreciate it.