My Colt NS is marked '.455 Eley', a commercial model, 90-95% overall. The bluing wear is all on the backstrap, like most NS. Lovely gun!
As for the odd grip frame, that's easily solved with a grip adapter or a custom set of grips that fill in the frame to trigger guard gap, leaving the backstrap exposed. S&Ws benefit from the same.
Even with the adapter, I have difficulty single action cocking the gun, finding it much easier to fire DA with both hands or thumb cocking with the left thumb as per any single action revolver. It's an awe inspiring gun, but no more so than a SAA, a 1911 (or any .44), if you were looking down that big hole.