Although I agree with your statements, I'll have to disagree with your logic there at the end. "could have or might have been made" irregardless of the degree of fit finish skill and technique does not make an article, rifle or other, "correct". Example, take an article oh lets say the best looking hunting frock or maybe a gorgeous regimental coat. Made from all the correct pattern, materials, buttons, dead nutz colors etc. The stitching that is seen by the naked eye is hand stitched, but the stitching on the inside seams hidden are machine done....is that coat "period correct"? How bout a nice looking wooden chest finished with wrought iron hardware, proper painted finish and lettering, but when you open it its an ice chest. Because you cant see the inside without opening, is that chest "period correct"? This is the trap you can fall into when you say "could have been made if..."
Thats almost as good as, "looks correct from a distance". I agree with you on the unknowns, there are only so many known examples of any articles we wish to copy and far too many unidentified examples. So what do you do? I think it better if refered to as "in the style of"...
To get back to the original post question, I have a rifle in mind that I am gathering parts for, it will be a percussion target rifle in the late 19th century styles. Think Schuetzen. I am not going to copy any particular gun but have a lot of reference materiel to draw from to make one that fits and works for me.