The screws and handle are wrong and the pommel looks like it came from Track of the Wolf. If someone is advertising that knife as an original to the ACW era nod and grin at them then walk away.
Rivets would have been far more common at the time than slotted screws. At the time screws were not all that cheap, especially small screws. Below are three pics of period style knives, though the bottom right is a Kindajl of the middle east. The top & bottom left are most likely period blades and both use brass pins or rivets. Good quality knives were readily available but not inexpensive, at the very least a pocket knife was common to most men. A side knife... gets more complex as there were considerable variation in style. The knife handle and hilt just look off for the period.