I had forgotten I had copies of US contract Chevrolet military truck photos.
1. 1941 MODEL YR Cargo 4 x 2
Compare with:
2. 1941-42 MODEL [Various as listed] Dump and Cargo 4 x 4
Note the US style front bumper which was a truck one for 1941 and not the car one.
3. The Holden-assembled equivalents seem to have used a major item, which looks more like a Canadian design. This is a YR Stake truck if US-sourced or a 1543 [or similar] if Canadian:
