The on-sale date is the publication date reported in the U. S. Copyright Office filing found in the Catalog of Copyright Entries, Part 2, Periodicals, New Series, Volume 34, 1939, Number 4. Class B periodical. Copyright number B 432170.
Per Fawcett Distributor trade magazine v3#7 (October 1, 1939), Fawcett Distribution Corporation was the distributor of this comic book
This is the inside-front cover
title from cover
Signed with a cursive "WBC" which differs from future issues in which Worth Carnahan would sign his art with a stylised monogram "WC" but the artwork appears to be the same.