Info needed: correct colours for WWII Aust vehicles

[Mrs Vampire]

I rubbed back a bit on the Stuart and found the following layers.

grey primer , US Lustreless Olive Drab, Black stencil, Australian Olive Drab , Australian light stone colour disruptive camo brush painted with plenty of runs, some red oxide applied in the seventies, Australian Vietnam era Olive drab put on in the seventies, areas of Australian dark olive put on in the eighties .

Photos below. I would be keen to know what the stencil ,means . It was original US marking XX! in an elongated diamond with ZZB below it. Looks a bit like a paint code.