Is “The novel's setting that Xiahou Mao is the son of Xiahou Yuan is fictional” true?

In chapter 91 of the novel, Xiahou Mao's background is written: "He was Xiahou Mao, the son of Xiahou Yuan. Mao, styled Zixiu, was extremely impatient and most stingy. From childhood, he was adopted as a son by Xiahou Dun. Later, when Xiahou Yuan was killed by Huang Zhong, Cao Cao took pity on him and married his daughter, Princess Qinghe, to Mao as his wife." However, the Records of the Three Kingdoms, Book of Wei, Biographies of the Xiahou and Cao families clearly records: "Dun's younger brother Lian and his son Mao had long been enfeoffed as marquises. Initially, the太祖 married his daughter to Mao, who was Princess Qinghe." In official history, he was originally the son of Xiahou Dun.