'Stoney' - I do not recognize the Receiver-Sight 'hole pattern' on your Krag.

The removal of part of the side-plate and some wood is suggestive of a couple of out-of-production Lyman gun-sights.

I am formulating a theory, but, have a quick question: Is the front hole,
(the 'ejector-pin' hole), threaded?

(BTW - The end of a Krag ejector-pin is normally proud and visible. The 'outside-end', of the small diameter pin, has a shallow groove machined around it, for easy removal.
Your pin likely has been shortened to allow the outer part of the hole to be used for a sight mounting-screw. The hole appears enlarged).