WW2 army uniforms varied...
Shirts were an OD wool, some are on the green side, others tend toward brown.
Wool trousers are the same way.
HBTs (Herring Bone Twills) are generally green, and much lighter in tone than the wools.
M1941 Jackets are Khaki, and M1943 jackets are OD #7 green.
Leggings are khaki or green, as is most web gear.
You really have to determine what time frame, and what unit, you intend to portray...Airborne is entirely different than Infantry... and you won't find too much OD#7 in the early war units, such as the 1st, 2nd, 26th, 29th, 45th, but you'll see alot of OD#7 in units like the 44th, 79th, 80th etc...
PS: You wanna get real screwy with uniforms, try reenacting 1st Special Service Force like CobraHistorian...(yea, we've fought side by side for a number of years).
Jeff Herne
Director, NJAHOF
www.njahof.org