I hesitate to say this, because there's going to be a deluge of replies castigating me, but the predominant color of uniform in MS in the early war years was gray -- gray coat & gray trousers. Lots of variations, but the majority during the early war was surely gray on gray.
Good admmixture of blue uniforms, with an occasional green or red (!), followed by butternut later in the war, and, finally, pretty much any thing you could obtain to cover your nakedness.
Now I will just sit back and await the opening of the floodgates! -- Jim Huffman, Gainesville Vols