Is “Capturing Fang La with one arm” true?

In the novel, Wu Song loses an arm during the campaign against Fang La and captures Fang La single-handedly; however, the "History of Song" clearly records that Fang La was captured alive by Han Shizhong's subordinate general, having nothing to do with Wu Song. The original text states: "即挺身仗戈直前，渡险数里，𢭏其穴，格杀数十人，禽腊以出。" (from "History of Song: Biography of Han Shizhong").