Queen Anne Dining Chairs

4 Queen Anne style chairs.   They have been stained and have been reupohlstered several times and plastic protectors have been added to the feet.   Two of the chairs have had to have 2 of the 4 seat support pieces replaced but everything else is original.  It also looks like it was had carved because not every curve is the same.   I am just curious as to when they were made and what they would have been worth.   I have since painted and reupohlstered them to resell.   I paid $80 for all four of them.   There are no markings but the lady I bought them from said she had dated them from around the 1700's by searching online.