Your serial number indicates that your Glenfield model 20 bolt action was made in the year 1980.
what year was Glenfield model 20 serial number 19721065
1980.
your marlin/glenfield was made in 1974.
With the serial number that you have supplied,your Marlin(Glenfield) rifle was made in the year 1980.
Your Glenfield model 60 was produced in 1989.
With the serial number that you have supplied,your Glenfield rifle was made in the year 1973.
1979.
1975
1975
Your Glenfield model 25 was made in the year 1988.
Your serial number indicates that your Glenfield model 25 was made in the year 1976.
The AB prefix to your serial number indicates that your glenfield was made by the marlin firearms company in 1966.
With the serial number that you supplied,your Glenfield model 60 rifle was made in the year 1978.