[motto]

Going by the very much modified front mudguards on the Chev in post #7 it has been 'Australianised' but not completely. As Mike K says it is an American cab as evidenced by the one piece side windows. The cowl vent is another giveaway. The truck is RHD.
An anomaly appears in that the fuel filler neck is still on the original (R/H) side instead of having been shifted to the other end of the underseat tank as most were.
The tray body is not the American L/L pattern and is obviously fitted with some form of seating. The fellows in the rear row appear to be standing on their seats and an extra board is mounted on the side to provide a reasonable backrest.
As usual with these trucks the mix and match of components has a 'use what's available' feel about it.

David