I believe the screw spacing was changed to 3.44, which allows for a full rear pillar instead of the notched pillar on all previous model Savages. It was originally just on dual port actions when Savage introduced them, but has since trickled over to LP and RP target actions as well. Surprised it took them so long to switch over.

With both screw spacings out there do what Sharpshooter suggested, measure before you order. Its the only way to be sure youre getting the correct one.