I visited the Woodbury MN Cabela's the day before yesterday and they had two parkerized 870 Wingmasters in the used rack. These were well-used older production and looked like PD trade ins. I was not able to inspect them other than a cursory exterior once-over.
Both had 20" barrels with factory rifle sights, short or no magazine extensions, and were fitted with Magpul stocks & fore ends, one black, one FDE. Price for each was $350.
(612)255-0000