Check the auction sites or find a copy of the Blue Book of Gun Values.
Simply subtract the first two digits from the number 2000, your rifle was produced in 1981.
Glenfield Model 30A, caliber is .30/30. Value is $125-$200 depending on condition. sales@countrygunsmith.net
Your Glenfield model 30A was made in the year 1979.
With the serial number that you have supplied,your Marlin(Glenfield) rifle was made in the year 1980.
1980, about $175.
1982 production, $200-$225 in excellent condition. sales@countrygunsmith.net
1975
1982 production, $200-$225 in excellent condition. sales@countrygunsmith.net
The Glenfield was made from 1973 to 1983. In the last production year, Marlin changed the model to 30-AS. In good condition, it's a very good deer rifle.
Your Marlin Glenfield .30.30 model 30A was made in 1974. For this perticular rifle, take the first two digits of the serial number (Yours are 26). Subtract 26 from 100, and you get the year of manufacture, which is 1974. Hope this helps.
The Glenfield brand is part of Marlin firearms. The most definitive answer will come from Marlin. And the nice folks at Marlin Customer Service just told me that your rifle was made in March of 1972. As far as value, depends on condition. In Excellent condition, these currently sell for between $375-$400. The 30A is a slightly plainer version of the Marlin 336- an excellent rifle.
1980.