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.