Can't answer for the Kiwis, but we Yanks had full duals in ALL or our Hueys. I've never seen a modern aircraft with partial duals, althouogh my understanding is that some very early helo had'em.
All my checkrides were flown right seat, but some ACs (aircraft commanders) prefered the left, better vis as there's less panel before you, and likely took their rides in that seat.
I have met "Viet Nam Vets" who'd tell you stories, sometimes actual lies. Not me, of course.