Yes, the boar is first traced on damp leather and then lines are carved with swivel knife.
After carving I used various beveller tools and mallet to stamp the outlines and give 3d look. Texture of the background is stamped with a tool named backgrounder (there are different types and patterns). Then the leather is left to dry.
After drying I apply antique finish, it has a form of dense paste. You apply it on the leather and then wipe off the excess.
After drying I apply special finish to give it water resistance.
RE: Thor's hammer bracelet