Title of the comic had an exclamation mark with it in the 1980s, but it seems to be just a part of the graphic design (as the title was in a word balloon) and not really a change in the publication's title.
Start year of 1939 confirmed in the submission to the U.S. Copyright Office recorded in the Catalog of Copyright Entries, Part 2, Periodicals, 1941, New Series, Volume 36, Number 3.
Format
Publication Type:
Comic Books
Color:
black and white
Dimensions:
oversize magazine size (10.5" x 15.5") (1960s); legal paper size (8.5" x 14") (1980s-1990s)
Paper Stock:
glossy cover; newsprint interior (1960s); thin card stock cover; white bond paper interior (1980s-1990s)