First of all, I have never worked with a Red Label; but having said that; I have worked on a few No.1's.
I thought it would be very similar to a No.1 senerio; so I looked at the Brownells site, specifically in their gun schematics area. There it shows the grip cap being held on with a wood screw and the screw cavity covered with the smallish brass eagle cap. They say the cap is common to the No.1 and a certain serial range of Red Label, you might check that out for yourself to be certain.
The typical removal of said cap will usually ruin the brass medallion. I carefully drill a smallish hole in the brass cap, and then use said drilled hole and a small punch to pry out the brass cap. Respect the side of the steel cap while doing do; mars on the grip cap are not good. The brass medallion cap is held in with friction, but is fairly tight.
I have thought about non destructive methods, but usually just drill and pry and get it over with.
The little brass ditty is available in parts in various sources, Brownells, Ruger etc. Once one is happy with all the new stock, fittment, etc, the little newly acquired cap is tapped into place.
Take a looksee at the Brownells or Ruger site and see the diagram.......see if it makes sense to you; after all you are the one going to do it......................nothing to it.