The Audit Bureau of Circulation files reveals that there were three printings of this issue in 1939 (500,000 copies, 250,000 copies, and 150,000 copies) (researched by Russ Maheras). The only difference noted is in the house ad for Action Comics #14, which has either an on-sale date of "June 2nd" or just "Now on Sale" (researched by David Bachman).
There is no number on this issue.
On-sale date from the publication date reported to the U.S. Copyright Office found in the Catalog of Copyright Entries; Third Series; Volume 20; Part 1; Number 1: Books and Pamphlets, Including Serials and Contributions Periodicals, January - June 1966, Renewal Registrations. Original copyright registration number AA299871. Renewed 1 July 1966, copyright renewal registration number R388937.
Originally reported to the Catalog of Copyright Entries, Part 1; Group 2; Pamphlets, Leaflets, Contributions to Newspapers or Periodicals, Etc., Lectures, Sermons, Addresses for Oral Deliveries, Maps; 1939; New Series; Volume 36; Number 4.
May 18 on-sale date also listed in house ad in Action Comics #13.
The Superman logo for each story was hand-drawn by Joe Shuster so they look different for each story and do not follow the cover official design fully.