Impossible to answer without a DETAILED description of ALL markings.
http://www.histandard.info/PDF/Sears%20Shotguns.pdf
how you con trace an old "sears sabre saw',model 315 277769 6612?
This model was made by Daisy for Sears. It's the Golder Hunter model 98 made in 1958. It's very simular to the Daisy model 141.
http://www.histandard.info/PDF/Sears%20Rifles.pdf The model 25 will have a two letter assembly date code onteh barrel.
Old Sears Catalogs
1971-72 model
What model????
No sn data available.
1967
They were mass produced from 1963 to 1967
Your shotgun was made by High standard in 1960 for Sears. The model 21 was first introduced by Sears in the spring of 1958.