Installing sling studs on a synthetic stocked rifle is not difficult.
The forearm stud hole is drilled and counterbored (barrel channel side) exactly like for a wood stock.
The buttstock hole is drilled for the stud, except that if the plastic is not strong enough (some thermoresins are too pliable) to hold the threads, you drill the hole oversize and epoxy glue it in place. I would dril and try to thread the stud in first. If that is not strong enough, redrill and epoxy.