The on-sale date is the publication date reported in the U. S. Copyright Office filing.
Copies exist with stamp "Rec'd Sep 19" - presumably, 1955.
The name 'JOHN TARTAGLIONE' appears on the splash page at a 90 degree orientation to the page, but does not appear to be rendered directly by any drawing/writing instrument (unlike the job number where none of the '9's are perfect copies of the others). Rather it appears that the panel was labeled with his name using some kind of typeset process (like a very tiny headline might look for a newspaper or magazine article).
This is how Tartaglione signed his work for a period. It's a stamp.
There is a small art panel in the middle of the last page of this story. The two pages of the story are separated by the following comic story.