Yes. I have one "good" source (Scale Aviation Modeller International - October 2004) that is respectable, and it states it is a very dark brown-green color.
There are also 2 decal sheets from Aeromaster decals, Eagle Strike Productions, for 2 aircraft in the same unit (one with red stripe, one with red arrow) that lists it as "chocolate brown". There is a third decal sheet from "Flying Papa's" (no idea how reputable) that shows it in a shade of dark green.
Finally there was one last decal sheet I found that said to paint it black, but in the same sentence said that some sources claimed it actually dark brown in color.
So I think the consensus is that it wasn't black. Majority vote