Factory new Remington 870 police barrel is 18.5" factory parkerized with fixed I/C choke and XS Low Profile rifle sights, 3" chamber. It is part number F249630AS on the Remington parts list and retails for $239.38. The sights are not tritium and Remington does not make the barrel in Tritium.
The Modified version is F404691 and also list for $239.38. I recommend the modified as it is great for slugs and stabilizes the slug better then IC. You get a tighter pattern at about 7 yards further out, but no choke affects range just tighter pattern at a further range. However if you are LE and have your ammo issued, select I/C as it is best with all brands and Flight Control