I've been told by the Performance Center that the MIMs don't polish up as well, and by my local S&W certified longtime gunsmith that the results are not the same.

As far as polishing engagement surfaces goes, honing & stoning have been done on those in Smiths & other guns for decades.
It's part of what constitutes a true "action job", as opposed to merely swapping into lighter springs.

Keep 'em at least very lightly oiled & there should be no problems with galling, especially in non-stainless surfaces.
Deliberately introducing lube-retaining scratches on mated working surfaces is a new one on me.
It was never brought up at the brief S&W armorer's school I went to years ago.
Denis