'KragOmatic': If that used barrel did not have the Krag 'extractor notch', it probably was not a Krag barrel.

BTW - The Criterion barrels use a different rear-sight screw thread than original barrels. Original Krag sight-screws will no longer work.

IMHO - If I were buying a Criterion barrel and having the CMP install it, I would have a replica Krag front-sight base installed. I would also get a 30 inch barrel.
IIRC - The price is the same and resale would be a lot better.