No birth certificate available for I 485

[hellvkl]

I am trying to file I -485 for my dad, one of the document needed is his birth certificate. He was born in China in 1935 and no birth certificate was issued back then. He does have a notarial certificate of birth (Gong Zheng Chu) from China's Notarial Office. Does he still need to have 2 affidavits from relatives or is the notarial certificate good enough to fulfill the record of birth requirement?

[immihelp]

https://www.immihelp.com/birth-certificate-for-us-immigration-and-visas/