Well, assuming that IS the real ANH facemask (there was only one as far as anyone can tell) it depends on when the photos were taken. The facemask was repainted AT LEAST once after filming.
As for the HT ANH helmets, it’s not just the tubes. While it may still be debatable that the tubes on one side might be black or gunmetal, there’s no doubt that the other side tubes ARE gunmetal. But then there’s also the issue of the eye sockets (gunmetal on the figure, black on the real deal), one of the triangular shapes between the tubes (should be black and isn’t), and some other panels (sides of the mouth, for example) that are black on the figure but should be gunmetal. There’s lots of innaccuracies on HT ANH 1 & 2 helmet paint jobs.
Interestingly, from what I can see in pics of the HT R1 helmet, it seems to be spot on with the black/gunmetal pattern.
EDIT
There’s tons of good reference on the propden forums. Unfortunately most of their image galleries are uploaded to photobucket. While a huge pain to work with, amazingly the images still work. Looking through their plethora of on set photos and screenshots, I’m convinced the Efx paint scheme is totally right for ANH (and hot toys got it all wrong on both ANH figures)
Here’s one pic that is a strong contender for all tusk tubes being gunmetal.