Most of the metal parts on this 'cut-away' Krag look like they are an excellent 're-finish' to me. (Just my humble opinion. I have not seen such a U.S. Krag specimen before).

My experience with legitimate 'cut-aways' was involving Pre-WW1 British Arms. These were used to train Armorers. They were an interesting curiosity, but, did not bring as much money from collectors as a working firearm.

In the last ten years at gun shows, I have seen some well done 'cut-aways' that were done by 'hobbyists' and sold as such.

BTW - This Krag 'cut-away' did sell at auction for $2,100.

I am a bit skeptical of it and the '1901 Pan American Exposition' story certainly does not wash. (It is super cool).