The Martin B-26 interior is supposedly largely unpainted, to move production along.
The cockpit interior had mats for insulation, which were green (take a guess).
The bomb bay was unpainted. Hey, if that's wrong, you can always paint it, anyhow, afterward.
I'd go with bronze green for the earlier, and chromate green for later production.
There's a build article on the kit you're doing in Finescale Modeler, by Rafe Morrissey, January 2005 issue. He says interior green, 34151, and unpainted bomb bay.
I'd say take your pick, until the erection manual for the B-26 shows up, if ever, and even then!
As they used to say "Don't you know there's a war on?"
Good luck, watch the gaps in the wing to fuselage join, and ditto the nacelles.
