From an edition of 128 this is hand numbered 1/128.
Please note this poster does not include the line of text reading NATIONAL COMMITTEE FOR A SANE NUCLEAR POLICY 17 E.45 ST. PREPARED BY GRAPHIC ARTISTS FOR SANE. The poster does not appear trimmed and as it is number 1 of the edition, it seems likely that the poster was printed as shown and the printers information added to later prints.