You should have no issues. The early Rigby Cocking-piece aperture sights did not have a diopter knob, but simply had the post that was raised and lowered manually by loosening a lock screw. I would prefer this arrangement for any open sight bolt gun, as I would not need to raise and lower it all the time. This would be especially true for an Ele/Dg gun. I bought one of Gottfied Prechtl’s Rigby diopter sights. It was too big and heavy for my taste, and I decided that if I were to mount a Cocking-piece aperture sight, I would go with the early non-diopter version for the reasons I mentioned. I sent that Prechtl/Rigby diopter sight on down the road.