Can't be answered without the name of the maker.
the age of a model 12 shotgun can be determined by the serial number.
I will need the serial number before I can age your model 12 shotgun.
1950
1937
Impossible to answer without the serial number.
1936
Your Winchester model 12 shotgun dates from the year 1941,with the serial number provided.
With the serial number that you provided,your Winchester model 12 shotgun was mad in the year 1955.
With the serial number that you provided,your winchester model 12 shotgun was made by winchester in 1927.
your Winchester model 12 was made in 1970.
Your serial number indicates that your Winchester model 12 shotgun was made in the year 1919.
With the serial number that you provided,your Winchester model 12 shotgun was produced in the year 1928.