Atlas Arms in Chicago offered replacement barrels for Smith and Parker guns using tubes made by Vickers (England) and fit and finished by Armaf in Belgium.
Some Smith and Lefevers were rebarreled by Armi Sarezzo and by one of the Bernardellis of Brescia; handled by a firm in FL named Hardin and Knight, but were usually Boehler steel.
You might ask
Ed Good for up close in focus images of the barrel flats, and review his return policy.