Screws
They aren't screws. The legs are hollow, and the tube is secured in place with a tool that spreads the ends. Unless you have the tool, don't try to jerry-rig it. You'll likely crush the tube. Most gunsmiths have one, and it's a 5-minute job.
If your left side grip isn't made of spongy rubber and the panel is to-spec , with a small entension at the top that curls around the side and bottom of the tube, you can effect a pretty good expedient fix until you can arrange to have it done.
Loosen the grip a little and slip a thin cardboard shim between the tube and the panel "ear" until the edge touches the frame. Tighten the panel screws, and use an exact-o knife or something similar to trim the cardboard flush with the grip panel. Done correctly, it can last for years or until you remove the grip.