FYI, I was looking at a vintage Qreen Anne style powder horn thinking seriously about purchasing. It was expensive. I don't see them very often if at all. The dealer also had a whetstone horn very similar to the OP's horn and closely matching the powder horn I was considering. Then I noticed a "witness" mark plugged hole where a belt clip was originally attached to the powder horn. I didn't buy the powder horn even though the patina on the horn base plug, etc. matched that of whetstone horn and knowing the dealer my comfort level wasn't there. It could have been a conversion make-do but not for me.