The item is clearly a genuine period made specimen and the presence of age damage (including the missing lug) does the item no harm at all.. except if you intend to sell it to some boof-head who suggests the item should be discounted because of that.
We all know the rules, never ever deal with boof-heads anyway
Nice find, enjoy that piece of history and every single age mark on it... they are ALL part of the item's history.
Regards and thanks for sharing!
Mark