As far as your SBD goes, it depends upon what part of the war you are depicting. In 1942 and into 1943, USN (and presumably USMC as well due to their being part of the Navy and following of Navy Reg.s) painted their bombs Light Gray to match the bottom color of aircraft. If the aircraft is in a "tri color" or overall Sea Blue scheme, OD for the bombs. But if in Blue Gray over Light Gray, Light Gray for the bombs is a good choice.