Is “Master of the Birthday Gifts” true?

In the novel, the hundred thousand strings of birthday gifts seized by the Liangshan heroes were a tribute to Cai Jing; however, there is no such record in the "History of Song", and the clever seizure of the birthday gifts is entirely a literary creation of the novelist. The original text states: "Each cart had a yellow flag inserted, on which was written 'Presented as birthday gifts to the Grand Tutor.'" ("Water Margin", Chapter 16)