I got to tour the J.D. Davis Gun Musuem just outside of Tulsa OK.
Mr. Davis had an incredible collection of "Kentucky" rifles.
There were numerous displays of 15-20 rifles by location. You could see by display that the style, the hardware, all varied by date and location. Southern rifles noticeably had little to no hardware on them.
Cannot say much of anything about the rifle in the pictures. There is just not enough information.
Your father in law is greedy. You are under no obligation to give him any money for anything.
If he wants a $1000, let him find a buyer.