'Ora' - That is a high serial number.

Be aware, many online 'sources' can feature poor information.
(Bowers has a bad reputation on the KCA Forum).

Frank Mallory listed at least eleven Krag rifles, with serial numbers ranging 480778 to 499036, which would be higher than yours.

(These were Krag serial numbers found in surviving official documents. They represent only a small percentage of actual Krag production).

Krag production may have stopped at the end of the 1903 'Calendar Year', which would have taken it into the 1904 'Fiscal Year'.

The NRA did not buy and sell Krags.

In the 1920's, the Director of Civilian Marksmanship (an Army department) would sell Krag Rifles and Carbines to civilians, who were N.R.A. members.

In the 1920's, Benicia Arsenal altered Krag rifles, for an additional charge, into 'so called' "NRA - DCM carbines". The rifle barrels were shortened to 22 inches and a Springfield 1903 front-sight was installed. These 'carbines' can only be documented with a D.C.M. bill-of-sale.

At times, the Ordnance Department auctioned off Obsolete surplus gun parts and Ordnance items.

Bannerman's, Stokes Kirk Sporting Goods, and others, were regular auction buyers and got creative making Arms for the civilian market.

Photos of your Krag, when it arrives, will beget more observations.