If it is marked Light 12, that is an incomplete serial number.
1979
1958
This gun was made in 1953
This gun was made in 1955
1973
50-500 USD. Browning will have to tell you the age.
Your browning light twelve was made in 1972 as the number prefix suggests.
Made in 1966
@ 33 years old
the 9Z prefix dates your browning to 1959.
your browning auto-5 light twelve gauge was made in 1960.
1966 light twenty auto5man