BudsGunShop.com - Magazine

No it does not Brandon, because if the addition of a detachable​ ​magazine​ ​feeding​ ​system​ ​in​ ​place​ ​of​ ​the​ ​traditional tube​ ​magazine.​ ​Pay no attention to that not-a-magazine tube under the barrel. It’s empty; there to guide the fore end as you cycle the gun. thetruthaboutguns.com/2017/12/dan-abraham/gun-review-remington-870-dm-magpul-shotgun/

Yes, however it is magazine fed rather than tube fed. If you take the magazine out, you'll only have one round to fire.