Sounds like a nifty drilling! I like the hammer guns as well as the hammerless....
It probably does have 65mm chambers, but the only way to tell is to measure them. Even then a lot of "short" chambers in older shotguns run longer than they're supposed to. I have a hammer Sauer/Daly 12x12x.30-30. One chamber is 67mm and the other 68mm.
I would also measure the rifle bore, as some are not what they're supposed to be. My wife has a "no name" O/U combo gun from between the wars that's marked 9.3x72R but has a .350 bore and .358 grooves.
What kind of engraving?
The name doesn't ring a bell but I will do a little searching.
