Information for this issue supplied by the Atlas/Timely discussion list.
First published work by John Buscema according to Back-Up #14 (edited by Tristan Lapoussière) (info via Stéphane Petit on the Error Tracker, January 2009).
However, it is not the first published art by John Buscema but it is his first professional art done.
The first published art is Lawbreakers Always Lose! #3 (August 1948).
Information from the John Buscema checklist compiled by Jim Vadeboncoeur Jr and Michel Maillot.