I've been clearing the goblin camps in Butcherblock a few times over and can say with certainty that if these drop from the goblins here at all (I've got none) they are a rare drop.
It's been a couple of years, but I have a vague memory of them dropping for my halfling in Misty Thicket and/or Clan Runny Eye, though.
Edited, Oct 1st 2022 8:43pm by Covalerahien