I imagine you could just install a set of
studs but I'd be a bit concerned about stock flex changing POI if you put much pressure on the sling. If you're shooting with a scope this is probably a good time to start looking at nice ridged as heck solid wood or laminated high comb aftermarket stock anyway and add swivel studs to that. Of course that's 10x the money of just adding a set of swivel studs.
One of my next projects is to add studs to this 10/22.