Some info so far..found here
http://www.kragcollectorsassociation...num=1430879077
"The 'Spanish War' was of short duration (April 21, 1898 to August 13, 1898). Model 1898 Krag production started July 8, 1898. Most U.S. Army Regular Troops were using Model 1896 Rifles and Carbines and most U.S. Volunteers were using 'Trap-door' Springfield Rifles during the brief SAW conflict.
However, in the Philippines following the defeat of Spain, the U.S. became embroiled in long conflicts, suppressing the Philippine Forces of the Rebellion, and then fighting an Insurgency. Model 1898 Krags saw increasing use in these later conflicts.
When the 1903 Springfield Rifle was adopted, the Krag continued in gradually declining use, as it was replaced. It eventually became primarily a National Guard arm. Numerous Krags were repaired, refurbished and rebuilt at Springfield Armory. During WW1, it saw use as a training arm and apparently with some 'rear echelon' troops (like U.S. Engineers and troops guarding French railways)."
Going by the serial # the rifle was produced in 1898, so its doubtful it saw action in the Spanish American War. They made 41,588 of them in 1898 serial number ranges were 64556 - 116146