'Florida Native':  Usually when I see a Krag stock with 'tiger stripe', it proves to be Italian Walnut.  The U.S. did buy some Italian blanks in 1899-1900, due to a shortage of seasoned stock wood.  This is not the case with your carbine.  The 1897 'cartouche' predates the U.S. purchase of Italian stocks.  I think the unusual 'tiger striped' American Walnut stock may explain the apparent mismatch of an 1895 dated receiver and 1897 dated stock.  "Somebody liked an attractive & unusual stock and put it on their carbine".  (My hunch).
  I see nothing altered with your carbine's muzzle.  It does appear someone substituted a much higher than usual front sight blade.
  Dick Hosmer is quite right in pointing out that the brass muzzle cap is a Rifle item and will not fit on a correct Carbine.  If it is Springfield made, someone skillfully altered it to fit.  I measured the muzzle of a Krag Carbine today and it averaged .645".  I measured two Krag Rifle muzzles and they averaged .615 to .617".  I measured the inside diameter of one of my Rifle muzzle caps and it averaged .623".  Thanks for the additional pictures and fascinating history on your ancestors!

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