I thought they were maybe white also old boy, as I seem to recall reading this when researching for my model, and I remember seeing a colour pic, albeit on a restored, airworthy aircraft. But I've just had a quick look at the Squadron Signal book and, in B&W photos, there's a definite tonal difference between the white of the landing gear legs and inside of the doors, which suggest zinc chromate, possibly green leaning towards yellow, as opposed to 'full' yellow.
I'm afraid I didn't make comprehensive notes regarding that area, as my model had wings spread.
EDIT:- We were posting at the same time. In the pic you've just posted, you can see the tonal difference on the wing folds, especially on the aircraft in the background, compared to the white of the wheel bays, gear legs and doors.