Go to Browning.com. They have a sn search function
The letters PN that are found in the middle of your serial number indicate that your Browning BAR was made in the year 1989.
The Suffix of M8 to the serial number dates your Browning BAR to the year 1968.
Serial number look up.
1968
1970
1968.
9 years old
The rifle is a Mark II BAR Safari, manufactured in 1995.
1972; 100-1000 usd
It is impossible to determine the age without the serial number.
That Serail number dates the BAR to 1986.
Browning serial numberb28564