[sharps4590]

I believe it's authentic. In my opinion I don't think you over paid. I couldn't find either Calvert or Leeds in my list of American gunmakers or in Boothroyds.

 

[sharps4590]

IF you're confident enough to remove the barrel from the stock, there should be proof marks on the bottom that will confirm the country of origin and a range of dates.

I'm very inclined to agree it is British in origin.