This might help you date your pin:
N.S. Meyer markings
In the 20’s : screwback, “N.S. MEYER, INC. NEW YORK” (raised), no shield
Early 30’s : screwback, “N.S. MEYER NEW YORK” + shield (engraved).
Mid 30’s to 1943 : screwback, “N.S. MEYER, INC. NEW YORK” + shield (engraved).
WWII : pinback, “N.S. MEYER, INC. NEW YORK” + shield (raised)
Late 40’s : Shield only (raised)
Late 40’s to early 50’s : “N.S. MEYER, INC. NEW YORK” + shield (raised and ½ size)
Early 50’s : “N.S. MEYER, INC. N.Y.C” or “N.S. MEYER, INC. N.Y.©” + shield (raised)
Mid 50’s to Mid 60’s : “N.S. MEYER, INC NY” or “N.S. MEYER, INC NEW YORK” + Shield + 9M (raised).
Mid 60’s to mid 70’s : N.S. MEYER, INC. NEW YORK” + shield + 22M (raised)
Since mid 70’s : N.S. MEYER, INC. NEW YORK MADE IN USA” + shield + 22M (raised).
Source : Militaria magazine, issue 272, mars 2008, p. 43.
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