Behind the Seat Storage

Is there a reason for the gap between the seat bottom & the cab, other than access to the batteries?
Adding a removable fill piece will reduce road noise
I’m going to stash a couple of tiedowns, something to kneel on, a meter & a tool roll in the frame work

The bench seat back doesn’t need the tek screws on the bottom. Smoothing the sharp edge on the bodywork where it intersects with the seat back keeps me & it from getting cut.