Mark, I wouldn't be too concerned about it being "historically correct" when a horn is that fine looking. I love the subtle but rich finishes, and the turning of the base plug. That is a beauty.
Regarding that original horn, who knows, maybe it was meant to be hung tip down. It has that brass valve, so perhaps the maker trusted that.
Jim Webb (who owned 200 original bags) noted that many bags had very short horn hanger straps. The horn was simply inverted 180 degrees to pour powder. No need to tip the whole horn up, you just flip it over. That is why the straps can be short. All of this came to mind when I saw the ring hanging the old horn tip down. One thing is for sure, if it is hanging tip-down, and you operate the valve, you get powder with no other movement.
Just my 2 cents worth, and I am no expert. Best wishes, and God Bless, Marc