chevrolet ID help needed

[nuyt]

Hi guys,
Here I am with some KNIL vehicles that need some ID-ing. They are probably all Chevrolet, but types and model years are a mystery to me.
The first one is the KNIL artillery prime mover from the 30s.
It is a 6x4 vehicle bodied locally, reportedly with Timken Detroit axles. There were at least two different versions: artillery prime mover and ammunition vehicle.

Enjoy.
Nuyt