I only wanted to post an image I found by mere chance online. Apparently, the shades of green on the Zaku II have varied tremendously over the years and sources: artbooks like Entertainment Bible, Gundam Mechanics, Gundam Fact File, Gundam Historica, the yearly MS Illustrated Encyclopedia and even online sources like Gundam.info.
I don't think this is a subject we'll ever see a final response on, unless Bandai/Sunrise/Sotsu settle for a single standarized set of shades from a color system, such as Pantone, PCCS, Munsell, Federal Standard, etc. Color is an extremely subjective topic.
Spoiler
My favorite is still the last one, heh, heh...