The Orion was originally built on Hesperus for the Terran Hegemony.
About a century later the K model entered production for the Star League. There is no indication the factory producing later model Orions was on Hesperus, and evidence that the design had already diversified.
By the time of the fall of the Star League production had already moved or spread (we don't know which) to Kalidasa in the FWL, it is strongly implied that ther houes also built the mech, and that Kalidasa is special for being a surviving factory location, not the only factory location.
Either the Hesperus Orion factory was destroyed by the First Succession War, or it was already gone before that time.