Those are not sack coats and with a 10 button front, I doubt they are frocks either. I suspect an early to mid war shell jacket, the high collar pushes me towards early, since the neck irritation would be such that the company tailor would lower it fairly soon. They appear to lack trim and the buttons also appear to be coat size (that is subjective since they have been painted over), so we should be able to eliminate federal shell jackets of cav or artillery.
The collars appear to have multiple hook and eyes.....there do not appear to be cuff buttons, so I would lean Southern, but it is really difficult to tell.
Because SC had the port of Charleston, cloth was readily available both imported and domestic; Reverend Anthony Toomer Porter's Industrial School for Girls in Charleston began manufacturing clothing for the state quartermaster. By March, Charles F. Jackson's clothing factory was furnishing the Industrial School with cut jackets and pants to be sewn and finished, then returned to Jackson's Clothing Emporium for sale to the state. The school had 32 sewing machines and the state could adequately supply uniforms to their troops.
Again, IMHO they look like shell jackets and Southern, but that is just a guess with the pictorial evidence provided.