Is the saddle built on a rawhide covered tree?To replace a horn is a labor intensive job,you have to tear the saddle down.Drop the skirts off ,pull the seat back,take the fork cover off.Remove the horn cover,then you will see if the tree is broke.To replace the horn you will need to order a repair horn.I charge 450 dollars to do this repair.If the tree is broke you will need to replace the tree,a 1500 dollar repair.Do the math and see if the saddle is worth it.
Steve