Hard to say...I've seen bomb drop footage where 500lb. GPs were yellow with green stripes on the nose, green with yellow stripes, and overall red...
It would also depend on the service branch...the bombs on the racks on the deck of the Hornet prior to the Doolittle Raid (when they were pinning on the Japanese medals) were obviously OD...
If you can give me some additional info, I can try to get some color photos from the period.
Jeff Herne
Modelwarships.com
Director, NJAHOF
www.njahof.org