I have an 1896 Krag that has a Lyman front sight.  I removed the Lyman sight and found that the sight dovetail had been filled in.  I bought a 1903 sight from Numrich that has a slot for a spline. 

I'm guessing that the spline fits into a slot (dovetail) in the barrel, right?  I read where another poster used a set screw to secure the 1903 sight on his Krag.  Other than cutting a slot for the spline, are there any other ways to secure the sight base?