I have chassis # 6 and it would appear to have been a kitchen, it has COUNTRY KITCHEN stencilled on the rear tailgate.
It has 85 stencilled on the Tac plate, maybe it was used by 85 trucks. Mine has a camo paint job, a covered in tin roof also camo .
I have no idea what the ARN is, the previous owner has misplaced the paperwork from where he bought it at auction in Brisbane in the nineties.
They are a beautiful well made trailer. Also thanks for clearing up the MBO manufacturer. I have only found one photo on the net of a canvas covered trailer or an uncovered one for that matter.
Ken