i don't think that's a vent you see on the rear door but a split as in the slider that might have been on the burb in that position, and the reason there's no ribs on the back edge is that the door is shortened [so no rollup window] .... also the ribbed hood shows it as a 57, and the pic that's been reversed is the one from the rear, the others show it is a right drive truck, with the gas filler on the left as usual but opposite the driver as on the vehicles built by GM Canada for export .... as joe says, 3rd party modification, or done by Holden in AU [for military probably, as a radio truck]
Bill
