Greetings,
I believe that "jungle green" is a closer description to the colour, but the kit/clothes would have faded pretty quickly in the climate over there.
The Australian War Memorial has a good photo site with lots of colour photos from Vietnam. Have a look at www.awm.gov.au.
I want to model Aussie troops from the Boer war to "now", so hopefully I get the time to also try and model some "diggers" from Vietnam.
Let us know how you get on.
Regards
Johno!