Saitiro
Hello Saitiro!
I had a couple of Schultz & Larson model 70 rifles. They both had what appeared to be the same sight as on your rifle. Keep searching ebay and gunbroker.com, as these sights have, on rare occasion, turned up. Unless you are wanting to keep the rifle completely original, you would be better served with a better sight, even if it means a gunsmith drilling and tapping the reciever.
Best of luck!
Greg