Old model standard Blackhawks (not 44 Mags) can be found with owner installed squared back trigger guard grip frames from Super Blackhawks. The grip frames readily interchange.
An old model 3 screw SBH would read: "Super Blackhawk" on the left side of frame. They would all have non-fluted cylinders and squared back trigger guards. It's a model #S46 with 6 1/2" barrel, S47 with 7 1/2" barrel, and S47B with Brass grip frame.
Model # KS458-N is a stainless steel, Super Balckhawk with 4 5/8" barrel, New Model with non-fluted cylinder. It does not have a squared back trigger guard. It has a standard Blackhawk size grip frame with round trigger guard.
Hope this helps,