Ken,
Attached is a 1945 "Pilots Guide to WWII Aerial Bombs" from the 303rd (Hell's Angels) Bomb Group at Molesworth. It may help you out with the colors and definitions of the different US bombs in use during WWII:
http://www.303rdbg.com/bombs.html Most 500lb General Purpose (GP) bombs were painted OD green, with black lettering, with a single thin yellow band between the removable tail unit and the body of the bomb. and in some cases another band around the nose of the bomb (but not always). Bombs were were fuzed with a natural metal fuze, and in some cases a grey or aluminum area around the fuze well was left unpainted. I think what you are seeing as "medium green" is likely an effect of the "colorization" of photos, or the processing of color photographs--but everything I've read indicates they were OD, but OD can also appear differently between manufacturers. There are also known difference in bomb body colors-- specifically pre-WWII bombs could often be found in overall yellow or in very light grey. This has led to misinterpreting these colors as "training bombs" which is not the case-- as there are many photos of these bombs being loaded for combat missions with definite HE GP bombs right alongside, especially early in the war before 1943. The difference in the location and number of yellow bands seen on aerial bombs is also due to the difference in explosive fill, Amatol and TNT are the most common (with the single band. Other types of fill would be designated by a different number of yellow bands usually on the nose of the bomb.
As far as B-17 interior colors go, they would normally be a standard "Cockpit Green", which is a bit lighter in shade than you have, and some later version would be painted a shade of Chromate Green (but sometimes the camera lies as to true colors too). However, again, depending on the manufacturer (Boeing did not build them all) the shade may be slightly different. B-17Es and B-17Fs were left unpainted from the radio compartment to the tail to save weight, as were some of the very early B-17Gs. Hope this helps. I did a lot of research on B-17s while doing my 1/16th scale waist gunner position for Large Scale Planes a few years ago.
VR, Russ