yes they will sometimes color morph. when i purchased mine back in march , he was a nice bright yellow. now he is a dull gray with black bands. i will try to post a pic here in the next day or so.
I actually saw a gray one at the LFS the other day. It looked just like a yellow watchman, but gray and it still had the blue dots. Not nearly as good looking as the yellow version.
Does this happen to all of them? And is there a way to tell if it will happen?