Go to Browning.com. They have a sn look up function under customer service
You must call Browning with the serial number to find out.
To determine the manufacturing year of your Browning BSS 12 gauge shotgun (serial number 6481A57), you can refer to the serial number dating guide for Browning firearms. Generally, Browning BSS shotguns were produced between 1977 and 1989. For the specific year, you may need to consult Browning's records or a firearms expert, as exact dating can depend on the serial number prefix and suffix.
1980
Made in 1972
1986
That is the number of a Japanese contract-made Browning BSS. Current online prices are in the $900-$1500 range in as new condition, less used. (May 2012)
1976
Made before 1975
BSS was made from 1971-1987
It was made in 1981.
YEAR 1973
1973