ETA: Mags showed up yesterday. The "used condition" shown on the site is not the used condition mine are in, just FYI.
Looks like one of these have been thrown down the driveway multiple times, not kidding.
Base plate is scarred and gouged, sides of some of the body looks like it was drug over rough cement. The other 3 are fine.
One was run hard, looks like some department's range or duty mag after going through multiple courses where mags are frequently dropped doing emergency reloads.
I'll clean them and see how they do.
To date, I have not had a single malfunction with any of my newly-purchased M&P .40 mags, which I have a range bag full of.
I don't like to spend time loading mags at the range, and prefer to focus on shooting, so I like to be able to grab fresh mags while I'm in the mode of honing pistol skills.
My expectation is that these mags will still run fine, regardless of how they appear externally.
If they don't I can re-spring them and maybe Cerakote them with Microslick.