Hello kmh48301@gmail.com,
Yes, the IFRs are separate from the main memory map.
It can be programed, erased and read as described in the RM rev.12.1:

Program Once Filed can be programmed only once - it cannot be erased.
It can be read using the Read Once FTFC command.

This Data flash IFR can be programmed using the Program Partition FTFC command and erased using the Erase All Blocks Command.
Also, the FlexNVM Partition Code is loaded to Flash Configuration Register 1 (FCFG1[DEPART]) out of system reset.
Regards,
Daniel