Excellent score, and I thank you for posting. I track these revolvers, and you just gave me a serial number of which I was previously unaware.
Here's a thread about the one I managed to acquire about six years ago.
Not to American tastes, probably, but still a nice revolver: the Model 11-4
Your gun was
not one of the several 11-4s sold at the Butterfield & Butterfield auction in 1996, but it may have been one of a few specimens shipped to Charles Greenblatt, a NYC dealer, in 1970. A Historical Association letter would be expected to tell you where it was shipped.
My tally of these Model 11 revolvers (non-model-marked or "Pre-11", no-dash, and all dash-stamped varieties) stands at 35. There just aren't very many of them around, at least in North America. Most of the thousands made were exported, with, one presumes, only a few dozens left here as contract overruns and the like before eventually making their way into the American commercial and collector market.