I'd be most uncomfortable with wood in the position you describe. My Trillium
certainly doesn't have any there...Above the generating unit itself there's a metal flap and all other surfaces are (nonflammable) fiberglass.
Especially given the recent rash of RV fridge
fires associated with wooden flued systems, I think you'd be wise to either remove the flammable wood, or if that's impractical, to install some kind of air-gapped metal liner .