Used Remington 11-87 Police shotguns for $450. Says they may or may not have side saddles but doesn't mention if all have rifle sights or not. Capacity is listed as 7 or 8 shells so it seems they all have some kind of mag extension. Limited time only.
https://www.sportsmansoutdoorsuperst....cfm/ID/298860
I couldn't resist and ordered 2.