OR Hunter:  Please check the Forum Topic "stock markings' a little further down this page.  I took the liberty of attaching the photo of the "C" marking on your stock to the topic so it would move up to this page.
  I think these 'rebuild' marks are overlooked, poorly understood, and ripe for research.  Mallory touched on them very briefly in the second edition of "The Krag Rifle Story".  He mentioned seeing a rebuilt Krag with the "C" mark, but did not know what facility it signified.