That Malcolm scope didn't originate with the Hawken rifle shop.The one I had on a similar rifle over 50 years ago was made in Auburn,NY.The false muzzle appears to be for a cross strip patch of some kind.The bar in wood lock looks like a nice one as does the rest of the rifle.This rifle in this condition is a real prize and well worth researching for whatever time is needed.The uncommonly big bore,the weight and craftsmanship indicate a purpose dedicated rifle.Look inside the lock for a name.Probably won't be one but it's worth a look.
Lastly,congratulations on such a find.
Bob Roller