Hey thanks for the mention
Estropelic,
I feel kenmoore is right on all accounts (well, maybe not about me being your best resource).
Carrying a firearm in a holster for any significant length of time will result in bumps, bruises, and holster wear.
If you want to touch that up, I think you will need to glass bead it to match the finish. Sometimes the bead is enough to hide a small mark like that. Otherwise you'll need to sand and/or peen the mark out first.
I bought my MK9 used and bead blasted it so I could see where I put my own carry/handling marks on it
Regards,
Greg