Matt,
Here's a New York City newspaper account (from the Troiani book) on their appearance.
The dress consists of a dark green frock coat, trimmed with red on the collars and cuff, gray pantaloons, trimmed with a red cord, and clothe caps of the same color as the coats faced with red. The troops are also provided with an overcoat of gray pilot cloth, made after the Prussian Army regulation; in fact, the complete outfit of the regiment is on the plan of the Prussian Army. The knapsack are to be of the most approved style, being sloped, so as to fit on the hollow of the back, and of a size and weight to contain a good store of outfit-the officers' uniforms are precisely the same as that of the men, with the only distinction of their shoulder straps and the lace on their caps"
You may want to add a little dark gray to your green mixture to give it a dull green look. Atleast thats how it appears in Mr. T's book.
Jason