Looks like you got a nice sporterized Krag carbine and extras! The extras add to the value of your purchase. 

Hopefully your carbine has good enough rifling to still be a good shooting Krag.

I'd only be real worried about making cracks look better if I had a valuable military Krag or if the crack was unstable and was going to get worse with handling or shooting. Yours looks stable enough to not have to fool with or worry about much.

Enjoy and thanks for sharing!