No idea on Vallejo colors, but...
Nomex CVC uniform is a medium green, ranges in shade from OD, to sage green, to a dark green.
They also wear standard 3-color DCUs and Woodland BDUs with either an IBA vest in Woodland or 3-color DCU for Army crewmen, or also the USMC Cayote brown (a dark tan color) for USMC crewmen. USMC crewmen could also be seen in USMC MARPAT digital unifors as well. Current Army crewmen in Iraq can also be seen in the new digital ACU (Army Combat Uniform) too.
IBAs
Woodland: 
3-color DCU: 
USMC Cayote Brown (with added shoulder and arm protection): 
MARPAT:
Woodland 
Desert 
ACU: 
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