This head has at least 2 distinct colour variations for its eyebrows (possibly
more).
1 looks orangeish/light reddish brown(?), and the other looks like it's reddish-brown/dark
reddish-brown(?). I'm
not sure but it might apply to the blocked head version also. it might be difficult
to see the colour variation in the photo but it's more visible in person.
If possible it might be good to add a note.
(the colour variation is visible across multiple heads and isn't fading)