If Tang Fengcheng copied Wang Xizhi's original handiwork Lanting Preface and put it up for auction, what's the valuation?

Generally, the original works of famous calligraphers in the Tang Dynasty should be more than 1 million. For example, Su Weidao, who became prime minister in the period of Wu Zetian, was said by insiders that his original works should be more than 1 million, while Feng Chengsu was given to the kings by Emperor Taizong in the period of Li Shimin because Li Shimin liked Wang Xizhi very much. After that, there was a dragon seal on the original works, which was the seal of the emperor in the era of Wu Zetian and Tang Zhongzong. There are more than 4 seal traces, and there should be Qianlong seals, so it is even more immeasurable. Wang Xizhi's Lanting Preface estimates that the auction price should reach more than 8 billion, so Feng Chengsu's should also be around 1 billion.