a slug gun and a shotgun are two different animals.
shot is for shotguns, slugs are for slug guns.
slug guns have rifle sights.
shotguns have beads.
this is why I teach (from the target back)on choosing a gun.
too many people try to bend a shotgun around a telephone pole trying to get it to do something it wasn't designed for.
for the op's sake I will say....if a bolt gun is going to be (converted) to a slug gun, then by all means, yes, it would be good, since the bbl is directly attached to a receiver.
so many people dump so much money into gadgets, especially pump owners, forgetting, the front sight on a pump is on a non permanent bbl and the rear is on the receiver. if the bbl loosens, you lose zero.
so for the op's sake, glass it if its going to be a slug gun....and no if its going to be a shotgun.