No. We also know who all of MaoMao's family is. MaoMao is unmistakably Lakan and Fengxian's daughter. Fengxian genuinely loved Lakan and wouldn't consider anyone else worthy of her. Maomao was born in the back rooms of Verdigris House and raised by the Old Hag and the Three Princesses.
This daughter of the previous Emperor would be a few years older than the current Emperor. Anshi had him some 30ish years ago. We learned last season that the Empress Dowager Anshi is in her early-mid 40s.
Maomao and Jinshi are only a handful of years apart. The "swap" that Maomao dared to speculate on before burying it in her mind forever is about Anshi's second child (we see the conception of here) and Ah Duo's with the current emperor. One of them died at childbirth. That's the incident that got Loumen's kneecap removed as punishment and his exile to become Maomao's adopted father.