How are the ratchet and other handles marked, Otg? Are there any markings (i.e., OEM) other than the brand? Do the sockets and the female drive bells on the extensions have the * mark where the detent balls on the male drive studs should be positioned?
If you mean catalogs, info is limited, and somewhat confusing (challenger as solo brand, challenger as sub-brand of Fleet, PENENS, Proto, and PTII, etc)for the later production.
The whole history of the Challenger line is strange.
It first shows up in 1940, on page 24 of Plomb Tools Catalog #19, for Challenger socket drive sets 4700X & Y, 5200 X & Y, and 5400 X & Y. Don (d42jeep) and Carla have some fabulous examples of these early sets. But it doesn't show up again in any 1940's Plomb or Plomb/Proto catalog. After a proud and bold introduction, it was immediately dropped.
In fact, the next time we see it show up again in public domain literature is a 1950-51 Woodbury Hardware Store catalog that four.cycle posted, linked
here.
Scroll down. Your set looks like a newer version of Set No. 301, with a steel handle instead of a leather handle. Otherwise, similar if not identical style of tools, and the same exact number (17) and types of pieces.