Ruger quarter ribs really come in two basic styles..............for scope only............and for scope/and/or iron sights. The iron sighted models, s, a etc have a dovetail milled with gib support for their little folding rearsight, the B for instance has no such dovetail/gib arrangement.
If one looks at the top of the rib, I might suggest taking the scope off via the mounts, large slotted screws(clockwise type). One of the nice things about the ruger quarter rib system is the ability to replace the scope on and off with very close zero.
Anyway back to the top of the rib, you will see four 8-36 screws distributed along the rib for affixing said rib to barrel. These 4 screw are either allen or torx type screws. You also see, if still factory, two steel studs for recoil. The recoil studs are very tightly fitted to barrel and rib........both the 4 8-36 screws and the steel studs will feature adhesives. So you might ask if you ever remove the rib without heartache or damage. Ruger put them on to stay, but can be removed with basic methods.
One screw is left on the top of the rib near the rear sight, a smallish slotted screw thru the gib; typically it is not put in adhesives, but use a good fitting screw driver and a little common sense.
these smallish parts for support of the rearsight.............gib and screw............original vendor has them or Brownells fwiw.