>>518613I happen to have a Hultafors Agdor hatchet and it has varnish, the colour is gray/silver (or maybe it's just the colour of blasted steel, I don't know). There is no varnish in the handle.
Their more expensive axes look more black in pictures, haven't seen any IRL, but I'm almost certain their finish is similar to GB and Wetterlings.
I didn't like the varnish at first and planned to remove it, but decided to keep it as it is until it get's too ugly to look at.