Not a problem, really. Weaver still sells their side mount scope base specific per rifle (I believe there are 4 bases). They have 2 sizes of detachable rings the accommodate either short or long 1" scopes. Bases Rings
One problem I often encounter when retrofitting these old rifles is that a lot of them were drilled kind of willy-nilly wherever the person drilling them felt was appropriate and then the mount (which was steel) would be bent to align the rings over the bore centerline. Current rrings and bases are aluminum and present a challenge to bend.