Arduino atmega328p unique id/serial number

ATMEGA328P_TEST.ino

//found this code here
//https://gist.github.com/speters/f889faec42b510052a6ab4be437d38ca

//Purpose is to simply run a memory check on ATMEGA238P to test for counterfeit parts

#include <avr/boot.h>
#define SIGRD 5
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("");
  Serial.println("boot sig dump");
  int newLineIndex = 0;
  for (uint8_t i = 0; i <= 0x1F; i += 1) {
    Serial.print(boot_signature_byte_get(i), HEX);
    Serial.print("\t");
    newLineIndex++;
    if (newLineIndex == 8) {
      Serial.println("");
      newLineIndex = 0;
    }
  }
  Serial.println();
}

void loop() {

}

Atmega328PB AU with just -U marking, which enters high voltage parallel programming with Nick Gammon's tutorial and schematic, so probably genuine, boot signature:
1E 56 95 1E 16 1 A5 A5
FF 55 FF D3 FF 96 56 30
56 4C 49 50 69 13 20 28
17 6 12 B 13 B FF FF