'jzitch' - Welcome to the KCA Forum.

Your Krag, #409344, was likely assembled in August or September, 1902, as a model 1898 rifle.

Model 1899 carbine production had started three years earlier, in September, 1899, around serial #226,701.

(I do not know where you found the information that your Krag was made in 1903-04).

The 'hammer' marks, on your front-sight, likely indicate the sight base was removed from a rifle barrel and reused on a shortened barrel.
IMHO - Your sight base appears crudely installed.

Years ago, lots of individuals and small companies made such alterations to Krag rifles to make them more useful for civilian Hunters.

You do have a real model 1899 carbine stock.

The absence of an 'Acceptance Cartouche' and a 'circled P stamp' could indicate it was a spare stock held for Replacement/Repair.
It maybe was never even used officially.