'Bill': Others, more knowledgeable than I, have said 'Bowers' is very incorrect on Krags.

It is very tentative giving a U.S. Krag an exact manufacture date, because of the way they were assembled at Springfield Armory. A numbered Receiver could have 'laid around' for a bit before it was grabbed and assembled into a rifle.

It is believable that your Krag was assembled in late 1898 or early 1899. An 1898 or 1899 acceptance 'cartouche' would more likely be expected.

It would be interesting to know which model rear-sight is now on Krag #153798? Armory updating of most Krag rear-sights required disassembly and removal of stock to change to required hand-guard. Your Krag started its service with the model 1896 sight.

I am not depreciating your Krag. It sounds like you found a nice one! A lot of this "development and updating" is part of what makes them interesting.