The Singer 301 was manufactured from mid 1950 to April 1951. Then they began the manufacture of the 301a from 1951-1959. The 301 should weigh about 16 lbs.
The Featherweight was made from 1933-1964 and is supposed to weigh 11 lbs.
There are several websites about the Singer 301 and literally hundreds about the Featherweight.