The on-sale date is from the publication date recorded in the Catalog of Copyright Entries, Part 2, Periodicals, 1943, New Series, Vol. 38, No. 4.
Busy Arnold stated in an interview that Moreira did do some early pencils on Kid Eternity material, but his inker was most likely Elgin.
Pencils credit from Bob Hughes.
All Gustavson credits verified and courtesy of Terry Gustafson, son of Paul Gustavson.