after further research it appears that the earlier guns did not but that the current production does have a flash hider and the can now be converted to 5.56 or 300 blackout by the addition of the proper upper and magazines details at ati link https://americantactical.us/5512/detail.html

Yes, Excellent pictures here : gunsinternational.com/guns-for-sale-online/rifles/ati-american-tactical-imports-rifles/ati-omni-hybrid-shotgun-410-gauge.cfm?gun_id=100941900 ------ google.com/search?q=ATI+Omni+410&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjiqKLU69zZAhXGTd8KHQG7AoUQ_AUIDCgD&biw=1920&bih=938#imgrc=Wme52Z2815qomM:

no it does not
Built on their patented Omni Hybrid receiver, the ATI Omni Hybrid AR-15 .410 ga. Semi-Auto Shotgun is a one of a kind shotgun wonder. Chambered for 2 1/2" .410ga shells, the Omni Hybri 410 is a must have multi-purpose shotgun. Offering an 18.5" barrel with a custom 13" keymod rail, the Omni Hybrid 410 runs on a gas operated, short stroke balanced piston system. Each Omni Hybrid 410 comes with one 5 round American Tactical-made polymer magazine. The Omni Hybrid 410 will only operate with the patent pending American Tactical polymer 410 magazine.

It does come with a "Flash Hider" Douglas. youtube.com/watch?v=KRkckflyNAo