Here is a checklist to help you Tony, I don't get into detail w/ all the E121-like potential backs on it but this is a fairly complete checklist for Mays...
Mays, Carl W.
• 1921 Baseball Mag Prem
• 1924 Diaz 8
• 1922 E120
• 1921 E121-80 May
• 1921 E121-80 Mays
• 1922 E121-120
• 1922 E122 May
• 1927 E210-1 17
• 1927 E210-2 17
• 1921/23 E220
• 1921 Exhibits
• 1928 Harrington’s 17
• 1922 Neilsons 7
• 1922 Neilsons Type II
• 1935 Schutter-Johnson 8
• 1928 Sweetman 17
• 1928 Tharp’s 17
• 1923 V100 / E123
• 1916/20 W-UNC Big Heads
• 1922 W501 29
• 1922 W501 103
• 1928 W502 17
• 1922 W503 20
• 1925 W504 130
• 1919/21 W514 103
• 1923 W515-1 20
• 1923 W515-2 20
• 1922 W573
• 1921/22 W575-1
• 1928 Yuengling’s 17
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