The serial number will be stamped into the action.
If you check the data base listed below in "Related Links" you should be able to find the date of manufacture,
Your winchester model 70 was made by winchester in 1965.
Your Winchester model 70 rifle was made in the year 1965.
Your winchester model 70 was made by winchester in 1954.
your Winchester model 70 was produced in 1966.
Your winchester model 70 rifle was made in the year 1973.
your Winchester model 70 was made in 1966.
Your Winchester model 70 was produced in 1949.
your Winchester model 70 was produced in 1966.
your Winchester model 70 was made in 1991.
Your Winchester model 70 was made in the year 1976 with the serial number that you provided.
Your serial number indicates that your Winchester model 70 rifle was made in the year 1971.
With the serial number provide,your Winchester model 70 was made in the year 1976.