I'd go with the original Dragonfly paintscheme. (Part of me did always like the Tigerfly cammo, but its pretty unrealistic outside of a Tigermeet gunnery competition...) The Dragonfly scheme would be the easiest to paint as well. For accuracy sake, I would research the exact shade of green drab paint used by the US Army in the late 1970s and early 1980s for the best effect. If you can get enlarged versions of the noseart and markings, that would add to the effect. If not,
www.cobrastickers.com has excellent reproduction sticker decals.
On an unrelated note, the GI Joe designers must have intended the Dragonfly to be a tiny attack helicopter, judging from the box pics. Obviously it was influenced by the early-model AH-1s, but the picture (as well as the actual model) are decidedly underscale.