I am going to post below two official shots of 1940 and 1941 MCPs. The bottom one is a CC60L 3-tonner, and note in both cases no quarter-light. I suspected that this was a Holden-built cab design but have never noticed it before!
The front bumper designs do vary as we have discussed before, with Holden using the US civilian lightweight design as well as the optional heavyweight and military style bumper.