You are correct, they were marketed under Safety-Streamline and Super-Streamline, or Streamlines when referring to more than one. Also to correct some other sloppiness, this one should be correctly identified as a Dayton Model D-1T the "T" being for Tank Equipped. They used one letter after the model to denote such things as "T" for Tank equipped, and "E" for electrically Equipped.
The Firestones were marketed as Fleetwood Supreme. Firestone had three tiers of bicycles, the top being the Supreme (whether it was a Streamline or not) the middle being the Standard and the bottom being the Sentinel. In 1938 there were 2 Supremes, the top one having the new "Twin-Flex Cushioning" and the second one being the Streamline called "The New Supreme" and looking in the catalog like a 1937 Dayton with a Firestone paint scheme.
Sorry, sometimes I get sloppy and anything could be the result. but this I believe is correct.