US Tank Color in Vietnam War

They were Dark OD, not OD 34087. It's very dark, almost a purplish black color.

I believe that the Marines' green was a definitely more-greenish hue? Somebody will help you out who knows for sure. soon.

Yes, the Marines used a deep bronze green in their ground equipment.

I'm not sure how accurate online pics are, but "bronze green" looks less vibrant than regular green and has some OD hue.  I'm thinking about mixing Japanese green and OD.  Would that be reasonably close?

Testors makes the Marines Bronze Green in their model master lines. For the Army's Dark OD, you can add black to OD and eyeball it.

I've always liked Humbrol OD, #66.  

Mud and dust. Welcome back doog