The answer to that is yes. There were ball and shot guns, in the muzzle loading era.
Of smoothbore, but heavier built breeches, barrels and stocks than typical fowlers.

Long time friend of mine, Wil Tompson of Smithers, now gone, had one in 6 bore, having 36" tubes seems to me IIRC
. When re-furbished by H&H in the 70's, they reamed it out to 5 bore to turn the rough tubes into like-new again.
Wil actually won a turkey or two with it, shooting trap. 2oz. shot and 120gr. FG IIRC. A light "square" load, that shot well.