I don't know if we ever get a good shot of him outside of all those shadows in the Snowspeeder cockpit, so I think his green/gray helmet might be one of those "blue coat/brown coat" type of things.
It looks wrong on the toy because it's so plain and gray and we're used to brighter colors on the helmets, but at the same time, based on the picture above, it looks like it's pretty much correct as far as I can tell (without a better reference picture).
The pictures also give, what I hope, is a false impression that he's actually taller that the already tall Gold leader.
Actually, yeah he is taller. If you look at the legs on Zev, you will see they are closer together and not as spread out as Dutch/Wedge. Also, having that extra "skirt" thingy between the waist and the torso peices adds just a touch to his height. The end result is that he is
slightly taller than Dutch/Wedge (at least on my figure anyway).