The Australian cabs feature a rectangular shaped air vent in the cowl sides.
The spare parts division of GM-H, NASCO, were manufacturing some mechanical parts. I have nos NASCO 216 main bearing sets. As recently as the 1990s, you could buy crates of Army surplus 216 dome pistons, Canadian made.
1940 Canadian Chevrolet Series 13 (1/2-t) utility (Australian) Lots of history here! Read ot all in the DITY