You know, I looked at that holster again, and don't see the adjustment screw of the Sloan model. I think it's just what Turnerriver said, a Heiser model with a hammer protector.

I have seen a few FBI holsters by Heiser, but don't think the leather came up high enough to protect the coat lining from the hammer. This was evidently just an alternative version, with a hammer protector.

That Combat Magnum/M-19 is gorgeous, and in wondeful condition!

T-Star