G&H lists sidemount installation labor starting @ $370.00. At anything close to that I think it would be worth having them do it. Given that you have a nice M70 putting a G& H sidemount back on it is the best way to handle the holes in the side of the receiver.
I've had several people plug the holes left in the action from side mounts by various means & have never been completely satisfied. A G&H sidemount is not a bad thing on a serious hunting rifle where you might want to have iron sights as a backup.
