I have seen them with the half octagon barrel but don't recall if they had the fore end cap and hawkin style butt plate. I think you have a post fire rifle that is when they started using case hardening on the receiver. That will also make the rifle a 38 twist as well. Sounds like a very pretty rifle can't wait till you post a pic of her.

I bet it will love bigshot sabots and good heavy conicals as well. with the 38 twist you could probabally do some good round ball work as well.