Would like to pick up the Remington 870 18" police barrel with rifle sights. I can not find a part number or anyone that stocks it. (They only seem to carry the 20" rifle sight version.) As this barrel is an option on several current Police models, I would have thought they would sell it separately but I'm not having any luck. If anybody know where to find it, I would appreciate it. By the way, Remington's customer service could not help as I did not have a part number.