Oily,
I can only provide a little piecemeal info about your 582 drag link socket:
I have a PDF copy of a 1975 Thorson tool brochure with a list of the tools available at that point in time. The only 1/2" drive drag link socket was a number 574 and the socket had the Thorsen Hot Forge Tools logo on it and no grooves.
I also have a PDF file of the 1958 catalog that shows the same 574 drag link socket with no grooves and an earlier Thorsen logo on it.
I suspect your 582 drag link socket is older than 1958, perhaps as early as 1940's. But this is just a semi-educated guess on my part.
Hope this helps some.
BTW-- What year catalog do you have access to?
Lauver,
Is the 1975 catalog you are looking at the one referred to as "3-75"? If so, and just for the sake of clarity, I don't think the "Hot Forged" logo appears in that catalog, does it? I see the number 574 drag link, shown on page 0-4, but I can't tell that there is any logo on the piece itself. The logo that appears on that page and throughout the catalog is very much like the "Hot Forged" logo, but slightly different. Also, the "Thorsen" address, shown on the last page of the catalog, is in Dallas. Here's the catalog logo:
The "Hot Forged" logo, registered in 1957, with Thorsen in Oakland, is this one:
I would also like to have a look at the 1958 catalog, but then again maybe not, as it seems the more you see the less you know when it comes to tool company histories.