Even a few authentic but relocated front sights exist on 22' cut down rifles but they won't be dovetailed and brazed. They made these in large number because there were so many rifles available, released from the arsenals, and comparatively few carbines, which were preferred. Usually they have a 1903 front sight installed (its banded) and are cut to approximately 22' (from 30'). I wouldn't call them fakes really, just an attempt at the time to make good sporting rifles with the qualities of the cavalry carbine. So many 1898 'sporters' were made in the early 20th century. These have been swapped and even faked (made from 1896 rifle sights, which are similar) in the past. Having the correctly marked (C) rear sight does not prove it a carbine but it helps a lot to have one. The absolute way to tell is if the action is stamped Model 1898, the barrel is exactly 22' long and the front sight base is the authentic Krag base, brazed into a dovetail slot, the center of which is about 3/4' from the muzzle.
The truth is, there is a little uncertainty about the serial number range for the 1898C and it's possible to have one outside that range but not probable (it would be the first). Yes, a true 1898C should fall into the serial number range mentioned if you want other collectors to accept it readily.
