I purchased a used 870 field gun and built one much like the one in your address.
I used a Choti (I think that spelling is right) stock with pistol grip much like the one your looking at. A Pachmier pump, and a rememgtion mag extension.
And a new slug barrel and diddnt have any where near that price.
Gun was about 250, stock 100 and pump 35 and the extension around 70 slug barrel 85.
You can get flashlights any where and most of the parts you can install your self very easly.
So if you have to have a new Police MAX go for it, but if your looking for a good home gun then buy a used and build it your self, youll be happier both ways, but a lot more satasfied being able to say you did it your self.
Below is a location for CHOATE stocks and they have then for as low as $62