I downloaded CCG3PA SDK, and installed it on my environment.
I found the firmware for CYPD3174 and CYPD3175 devices, and I think the firmware is for reference design.
CYPD3174 FW - 45W EZ-PD™ CCG3PA USB-C Notebook Power Adapter Solution using MPS
CYPD3175 FW - EZ-PD™ CCG3PA USB-C Mobile Power Adapter Solution using Power Integrations
Is this correct?
It is correct.
If you have any other question about firmware, it may be able to solve refer to see the CCG3PA documents on this page.