A standard US Army (non-Special Ops, 160th SOAR) Blackhawk is a dark green color. The color is called Helo Drab Green and is available from Testors in their Model Master lines.
A couple examples.
160th SOAR MH-60L in Flat Black, even some mismatched touch-ups.
160th SOAR MH-60L DAP gunship, Flat Black.
Standard US Army UH-60A in Helo Drab Green.
A standard UH-60L, Helo Drab Green.
Hope those help, good luck.
Gino P. Quintiliani - Field Artillery - The KING of BATTLE!!!
Check out my Gallery: https://app.photobucket.com/u/HeavyArty
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." -- George Orwell