I've never seen a storage bin on the rear of a coach...so I'm watching this thread to find out what it is.
Did you happen to look underneath the bottom of it? Perhaps it is for a spare tire but that would be pretty unusual.
2004 Monaco La Palma 36DBD, W22, 8.1, 7.1 MPG
2000 LEXUS RX300 FWD 22MPG 4020 LBS
U.S.Gear Braking System
Measure Twice, Cut Once