I am surprised more 'smooth rifles' are not in collectors hands as well. I know some of the ball and shot guns made in England for Africa had a raised square shaped silver centre lined 'lump' on the rib to give a rear point of aim when using ball in them for buffalo, rhino and elephant. Not had this, however. Here, it would have been called a rifled smoothbore - at leaat today.
The rear sight certianly helps, which is why certain people put on a highly domed upper tang screw to their smoothies, with the slot running North and South. This helps centre the head for windage, of course. I tried one and removed it from my .62. It ascued my elevation, but did help with windage.
Interestingly enough, until about 1820, in the hands of civilians, rifles dominated the prairies, however, side by side shotguns overtook the rifle into the percussion period and were more popular - for civilians, as well as some semi military units comprised of rebs. as well as union soldiers. It is reported they were loaded with shot in one barrel, ball in the other as Forsyth oft did in India when packing a favourite 14 bore smoothbore, or loaded with buck and ball or even straight buckshot, both in paper ctgs. in the .69's on the US prairies. The limitary load of buckshot was 15 balls of .32" for the .69's & was popular at some forts for shooting at prowling 'wolves' in the night. It was especially praised for nightime gaurd duty- "it was rare indeed, that a shot fired at movement in the dark didn't elicite a 'shriek' of dismay."