Take a moment and mic the factory recoil lug. You will find as much as .010 out of parallel. When you are looking at 1 1/8th inch dimater with something 20+ inches long being aligned by it you start to understand why it makes no sense to go to all that work and not replace it. At a minimum i would take a small very fine hone and "lap" in the face of the action and nut using light presure and a smal figure 8 pattern. There is more proud metal on an action face than you can imagine. The optimum would be to let someone true the face to the bolt raceway. Nothing more.