Well, the old Mannlicher-Schoenauer had a split rear receiver, so the rear mount had to attach to the left side.
The Paul Jaeger side mount is a good solution for a lot of these older bolt actions. With slim scopes like the Lyman Alaskan, you could use the iron sights under the scope, but the scope slipped off and back on to zero in an instant.
There was a hinged side mount which let you swing the scope out of the way for use of iron sights. I will scare up a photo and post that.