Even "sporterized" it's worth (unless there is some hidden flaw) at least 15X what you paid. If still in full military trim, it would have been 30X. Doesn't look too badly done. Sheard (made by Marble's, I believe) and Redfield were two very well-respected names in hunting sights. Redfield may still be in business.

Should be a fun rifle - as you say, the actions are VERY smooth. Great find! Ammunition can be had, though perhaps not at your very first stop. The .30-40 is more than adequate for any American hunting, within reasonable range. Might not be first choice as a "stopper" against an Alaskan brown bear, or for antelope at 400 yards, but it's no slouch, either.