You're correct for most infantry of D-Day...M41 Khaki field jackets with Khaki Drab wool trousers.
Some of the Ranger units, as well as some members of the 2nd ID, wore HBTs ashore, which were an olive green, typical of later war colors. Take a look at these sites for color photos of original and repro gear to get color ideas.
http://www.usarmymodels.com/
http://www.wwiiimpressions.com
http://www.atthefront.com
Hope these help.
Jeff