Is CONFIG_NETWORK_PHY_TIMESTAMPING=Y required for H/W PTP on AGX Orin?

With the stock Orin kernel we have CONFIG_NETWORK_PHY_TIMESTAMPING=N

My understanding is that this kernel option is not required to be set to Y for hardware PTP on the AGX Orin because the timestamping happens at the MAC layer, not the PHY layer.

Is that correct?

Yes, should not need it.