Oh to have faith in Chinese humanity. There’s typically no such logic behind product listings posted by Chinese companies. I’m only assuming here that the product is being sold by a Chinese company, but it sounds like it to me just because of the ambiguity. The EM4305 is also a read/write chip similar to the t5577 but it doesn’t perform emulation of other analog front ends.
https://www.emmicroelectronic.com/product/lf-animal-access-ics/em4205-em4305
Because of this I would contact the seller and ask specifically if it is an EM or T5 chip.