No.
Yes.
A smoothrifle would not only have front and rear sights (there were other smoothbores with both such as the Type-G or "Carolina" trade gun) but would have rifle stock architecture and most likely (but not always) rifle type furniture such as a trigger guard with a grip rail like most rifles.
Think of any of the well known or common early rifle styles, picture theor features. Look at early rifle examples such as, the "musicians rifle," the "Tulip Rifle," the "Lion and Lamb" rifle, the "Edward Marshall" rifle,,,, any one of these guns most likely had similar "siblings" by the same maker's shop that had no rifling in the bore.
With period ads listing both rifle guns amd smooth rifle guns, as well as fusils and/or fowling pieces in the se ad, it would lead me to believe there was more difference than just sights.
Period advertising not only lists smooth rifle guns for sale, but also advertises the service of "freshing" a rifle bore.
I could be wrong just working from memory but I don't recall seeing any ads for removing rifling, or boring it smooth. Not saying it was never done, but I think the case for worn rifles being bored smooth is weak at best. It was probably easier to cut the grooves a little deeper than it was to remove the lands completely.