butlersrangers wrote on May 23^rd, 2020 at 3:46am:

Springfield Armory bronze-brazed a lug into a dove-tail milled on the Krag barrel blank. This was done at an early stage in the shaping and manufacture of the barrel. In the course of manufacture this 'lug' took its final shape as the front-sight base. That is why the original Krag front-sight base is so nicely contoured with the barrel and the joint is almost invisible.

Well crud, that makes sense.  Thanks