I'm a bit late to the thread.
Sadly,, many of us have seen this damage to wood grip panels on Rugers way too often.
Yes,, as noted,, they can be repaired, but it takes a good knowledge of woodwork.
I'll agree that the spacer idea is excellent. Long before I knew Cary C,, and his making grips,, I was adding nylon spacers inside my Ruger SA grips. One thing I often found was that the 1/2" length was just a few thousands too long. it wouldn't allow the panels to seat w/o some movement. The grip frames were polished just a hair under 1/2" wide.
So,, I'd take the nylon spacers, GENTLY grind or file away about .005 off the length. Perfect in most cases.