SEGA PART #171-5364

1 Megabit PCB's - Date 1986

Each ROM has 28 PINs, the serial number can be found on the back of the PCB at the top near the center.  These title are amongst the oldest of Master System games, these PCB's were probably prior to the design of the 171-5519 1 Megabit PCB's.

Games like Choplifter have also been found using the 171-5519 PCB, yet the ROM MPR numbers remain the same.  There may not be any advantage/disadvantage when comparing one PCB to the next.  It simply may be a choice of what was available at the time.