Chad S. -  Your Krag rifle, #243746, likely had at least three different sights on it during its service career.
  When 1st assembled and accepted, it probably had the model 1898 sight, with three sighting notches.  This sight had a short use because it was not liked and was sighted for a higher velocity cartridge, that proved too 'hot' for the Krag action metallurgy (bolt lugs began to develop cracks).
  With a return to earlier cartridge ballistics, the 'model 1898 sight rifles' were fitted with model 1896 sights.  Most of these rifles subsequently were refitted with model 1901 or model 1902 Krag sights.
  With the adoption of the 1903 Springfield, the preferred Krag sight was the model 1902.  Early 1903 Springfields had a sight very similar to the 1902 Krag sight.
  However, in 1905, major changes were made to the 1903 Springfield.  It received a new rear sight which was similar to the 1901 Krag sight.
  There is some basis to believe, that Krags in use by the Regular U.S. Services, tended to be fitted with the model 1901 sight, while Krags in use by the National Guard tended to have the model 1902 sight.
  I would advise you to invest $20 in Joe Poyer's book, "The American Krag Rifle and Carbine".  The book is not without flaws, but it will increase your enjoyment of your Krag.

---