Might be tough to go the Mfg. They are in transition after being sold. There could be a fix if drilled off center by getting an undrilled base mount from Brownells and the mount can be drilled off center to compensate your receiver holes. Those old Weavers should have enough windage adjustment, unless the old B series or KV that the cross hairs do not stay fixed, and move the direction you make the adjustments. I can't recall if any make the old Redfield solid base where the rear ring retaining screw also served as a windage adjustment. You first need to use a bore sighting aid of either the laser type or the type that sports a scope type device on top with cross grids. That should tell you how much movement is needed to be dead on. It parallels the bore with the scope. Are your open sights level with the ground or are they canted? Off set scopes have been used a long time. For example, the M1 D and C Sniper Garands had to be off set to the left to allow a clip of eight to be loaded from the top. No other way could this be done. A local smith should be able to give you the answers you need, and should not be too costly. Marlin may have a repair center or a designated repair station even during their transition, that I think involves moving their location.
