Sorry, I have to agree with Mustang99. There is not one thing on that gun that looks like any Ruger revolver previous or since. The front sight, ejector rod housing, ejector rod head, loading gate, trigger, grip frame, hammer, sight, grip, cylinder pin, etc. etc., etc. Not one.
Any Ruger revolver from any era, single action or double, has easily distinguishable and recognizeable characteristics that can be seen at first glance. They may be slightly different, but you can SEE the family resemblance. The more I look at the pics, the more I'm certain there is not 1 Ruger part anywhere on this gun. Looks like somebody made their own rollmark stamps and had at it on their own creation. Not a Blackhawk.