Good possibility that any bulkhead would still be grey green, with the armour, and head armour, in black. But I'm not sure there was a bulkhead behind the seat though, just the armour plate, although I don't have my scale plans and cutaway to hand, to check. From memory, the back armour covered the width of the fuselage, looking a bit like a bulkhead.
Most seats seem to have been bare aluminium, with a khaki, or sage green quilted back pad, although I have seen pics suggesting the cockpit grey green.
Also, the raised 'gasket' behind the head armour, on the fuselage spine, was matt black, with the remainder of the spine in that area in the camouflage colours.