Browning.com has a sn function under customer service
1971
Auto-5 'Magnum Twelve' from 1965.
It will be marked where it was made.
B-80
A shotgun.
You have a magnum 20 gauge auto-5 shotgun that was made in the year 1967.
Is this an Automatic? Need the letter and number above the serial to help
Go to Browning.com and look for serial numbers under customer service
you have a magnum 12 made in 1966 auto5man
You did not provide the serial number. If you have it, you can go to the Browning web site and they have sn data. Also, the Blue Book of Gun values has sn data in it.
Serial number dates it as a 1983, Auto 5, 12 gauge magnum. FYI serial numbers start at 01001 at the start of each year. Without more information the best estimate on value I can give is 300-600