I do not remember really well what was used on the rear besides the American M series lights.
Logic would suggest the Aussie army would use a rear light already in the parts system from a Australian ACCO 4x4 truck made by International Australia.
This link shows what the lens look like.
P/N....857716R91
http://www.aussieedsworldofoldtrucks.com.au/lenses
Extra stop lights don't matter in Australia.......but a amber direction indicator does and usually mounted closer to the side of the vehicle than the American M series lights.
Amber clearance light on mirrors or cabin roof common in Australia from the late 1950s
Ron
PS
Phil would Know me as the 101 landrover and 1945 6x6 Studebaker man.
Another interesting thing is the Australian Army Studebakers were fitted with extra stop light replacing the original WW2 US army lights and Amber swing back clearance lights on arms from the cabin roof.
They also had a complicated yellow mechanical hand signal for right turns( left turn hand signals done by drivers left arm) and stop hand signal position on that indicator .
They were also marked Caution Left Hand drive.( even civie owned ex army WW2 jeeps at one stage)
Caution air Brakes was marked on some of the heavier Australian army vehicles.........but not now as air brakes are common.
It was all about the Australian army trying to get the vehicles to Australian road rule standards of the time.