Barrels were not automatically replaced. If they gauged OK, the barrel (and any other part, for that matter) were kept in service. The fact that you have a Hatcher Hole & new bolt indicate it went through rebuild at least once. Does your rifle have the Mk 1 trigger/sear; cut off & cut off spindle? Is the stock a Mk 1 stock? If it went through rebuild & kept those parts, it's a miracle!