Yea, I had a bad habit of selling almost every weapon when I first started. I have yet to get an axe with plateslayer, so idk if I never got hammer or if I just have bad luck with my drops.
The faceless are either a golden color or their regular green color. The green ones are aggressive and don't give as much exp and the gold ones run away. I'd say the amount of gold ones are probably around 40%?