I'd be interested to see if Teflon would help in that very heavily loaded area. After seeing the same wear on my R9 from the first shooting session, I worked in Brownell's Action Magic. That lasted less than twenty rounds.
The good news: After 200 rounds the scuffing had stabilized. At 350 rounds, the frame looks the same as it did at 200. And smoother to the touch. I can't feel any roughness with my 'educated' thumbnail.