Exactly two weeks after I sent it out, Fedex showed up at my door with a box not readily-identifiable as coming from Mossberg. Not being one to turn away a package, though, I took it.
I haven't had a chance to fire the gun yet, but my observations thus far:
I did notice that the extractor relief in the barrel seemed to have been filed, or had some sort of surface wear. Also, the packing slip indicates that they replaced the pusher assembly, the elevator, and the mag spring. The latter two items I'm guessing are in response to my doublefeeds.
There's a crapton of brass marks in the barrel/receiver, so I'm guessing they tested with "good" ammo.
Update tomorrow.