Nice work on the interior Bill.
Looking at the pic of the real aircraft, I think it's overall bare metal, apart from maybe OD rudders, and what could be an Identification colour, or possibly OD, on the vertical fins. This might also be the tone on the rudders.
If the aircraft was painted at one time, then the uppers would have been Olive Drab, and the undersides Neutral Gray (American spelling!). Personally, I think it was probably always bare metal, just going of the period when received.