Posted By:
fkw
If the card has a front like this one above (With the name below the photo) it is a E121.
If the first line on back ends in "eighty of the" it is a 1921 E121-80 Series
If the first line on back ends in "eighty" it is a rarer variation back of the 1921 E121-80.
If the first line on back ends in "120 of the" it is a 1922 E121-120 Series.
Like others said, If the card has the players name in a grey box it is a E122.