Here is an example from the historical artist Don Troiani, who puts a lot of research into his work.

http://www.historicalartprints.com/hap/cmd?CMD=DETAIL&parent=null&prodid=8

I would say the overcoat and trousers were pretty close in color as original items. You can imagine the impact of time, weather and campaigning on uniforms.

Russ

For enlisted men, the overcoat was the same sky blue as the pants. Initially, officers had dark blue overcoats.