Well, my thought was that the HKs' eye color is rather distinctive and has a small place in the story, seeing as it changes from orange to blue from HK-50 to HK-51. So, yeah, I guess I'm saying more on the orange side, haha.
I realized some of what I was seeing in the Atton shot was just the aliasing on the render. I think maybe touches of gray could help texturize the beard. In general it just seem flat, which is the problem I find with most facial hair add-ons. Maybe try adding a subtle ripple effect or some sort of bump map distortion over fractal noise? Just something to add more random texture to it.
Thank you Gorgod.