'olBear' - I am away from home and only have Joe Poyer's Krag book with me. I don't know how good this piece of data is and can't cross-check it.

Per Joe Poyer (page 163): "The Model 1898 rear sight was used on all Model 1898 rifles assembled circa serial #s 217,400 - 253,000."

Information in the Poyer book should be taken with a grain of salt and checked against more reliable sources.

The model 1898/Dickson sight has a lower base than the later model 1902 sight. It was calibrated for the 2,200 fps cartridge which was removed from service around March, 1900. The Dickson sight and higher velocity cartridge were short lived. It was intended the Dickson sight be removed and replaced.

Some 1898 sight parts got into the hands of surplus dealers and were potentially 're-used'.