I have a question about when did the US change over from the yellow color used on bombs pre-war to the standard OD color used during the war?
11 March 1942
Yellow Bombs manufactured prior to that date were "ert"...
I was watching Clark Gable's film about the 351st BG, and the ammo guys were loading yellow 1000 lb'ers in 1943.
Overall (no adjective) Yellow with black manufacturer's markings. It wouldn't be uncommon to find Yellow bombs in places after that date, since the ordnance would still be in the colors that is was painted with when it was made, so bombs with yellow bodies in 1943 would still be quite plentiful, as they weren't repainted after they left the manufacturer.. BTW , Whenever the US Military changes ammo color codings, they always make up a GTA (Graphic Training Aid) that includes both the new and old markings, just to avoid the possibility of some Snuffy getting it wrong...
U.S. BOMB, 1,000-LB, DEMOLITION HE, AN-M44, AN-M65, & AN-M65A1
The fundamental characteristics of Army "M" Series bombs are: Parallel sides, ogival nose, and boat tail (box type-tail assembly construction); and filled with 50/50 Amatol sealed at both ends with TNT surrounds. Some are now classified as obsolescent.
The Army-Navy "AN" series is similar to the "M" Series, except: (1) Third suspension lug added at center of gravity and 180 degrees removed from other two lugs, and (2) base plate changed to the male type. Since the development of the "AN" series, there have been two further modifications of the general-purpose (G.P.) bombs within that series, successively the "AN-G.P." and "AN-G.P.A1" modifications.
Prior to the organization of the AN Standardization Board in 1941, these bombs were designated as "Demolition H.E." bombs; under the standardization policy they were retitled as "General-Purpose High-Explosive (G.P.H.E.)" bombs.
And what was the color used, insignia yellow, the same used on prop tips and serial numbers?
I think you'd be safe with plain ol' "Paint, Yellow, Flat, Enamel, Testor's, 1/4 oz, #1169 "... Or whatever other brand you chose..
Keep in mind though, that different bombs had different colors overall, OD, Grey, and Blue being the primary body colors. OD denotes High Explosive, Grey, Chemical, and Blue, Practice. The bands and markings could be green, red, yellow, white, black, or purple...