It's just a single layer of 3/4"(5/8"?) plywood, so not much to worry about. My '08 Hawk also has some squeaks.
I suspect it's just flex when you step on the floor, rubbing against the non-padded truck bed. I entertained adding a rubber mat, but after checking with other owners, opted to go with the camper mounted direct to the rhino-coated bed. I'm not sure how FWC joins the ply at the corner of the floor pac, but certainly us mortals walking inside the camper shouldn't jeopardize that connection.