Not sure of your hunting enviroment but there have been many deer taken with smooth bores, every year. If it were I, I'd stick with the smooth bore or purchase a rifled barrel. In our Midwest states, smooth bores give good performance. ...
I did not know they made smooth bore slug barrels
A bit confusing but these are known as Rifle Sighted
barrels. Basically it has open sights. My old 1100 was this way and it was a killing machine. Weaver and I'm sure others, make a saddle mount/base for scope application.
Be Safe !!!