As stated in my original post, I thought there were two types of Lyman 54 sights for the Model 20. The early ones have knobs for both adjustments with the elevation on the right and windage on the left. The later ones have a knob for the elevation adjustment and a small screw for the windage adjustment with the elevation on the left and the windage on the right.
Now along comes this rifle:
https://www.gunbroker.com/item/1031573881 with what appears to be a third variation of the Lyman 54. (Photos 4, 10 and 20 show the sight well.) Note that the adjustment locations are in the same position as the early 54s, but the windage adjustment is now by a screw as in the later style. Was this a transition style between the two described above or ???
