Chuck, as a machinist of 35 years, I am inagreement regarding your preceedure.
I would only add that I might position the receiver on a verticle mill (bridgeport)and after getting everything indicated in,use a carbide boreing bar to get through the case hardened surface,at least on one side, and perhaps all the way through the receiver.
Also, I would think that a hardened dowel pin would maks a dandy hinge pin.
The radius on the barrels (the hook?) would need re cutting, based on measurements taken befor the job started.
I don't think this job is all that difficult, but it would probably take most of a day, so it wouldn't be cheap.
