As far as I'm aware, Trump's first term tariffs on China were Section 301 tariff...

As far as I'm aware, Trump's first term tariffs on China were Section 301 tariffs, and even though he floated the idea of IEEPA tariffs, he never actually invoked IEEPA in his first term [1]. Every article I can find about Biden extending and/or increasing Trump's China tariffs that mentions the legal authorization says it's under Section 301 of the 1974 act [2, 3, 4]. If you're aware of any evidence to the contrary, please share.