Hey Evan, in this case they were replacements supposedly in Natural metal with RLM 83 upper surface camo. So I painted the NMF and 83 separately so as not to have to mask them.
Now I also had another good reason for leaving them open....I like to think ahead on my builds and wasn't sure if the metal nose ballast was sufficient, worked out today when I attached the undercarriage legs for a test of the balance it was borderline at best 'just' barely having enough nose weight to sit right. So now I can add just a bit more weight in the forward nacelles to give the extra weight forward for better balance.