Eames shock with embossed 'S'  

sounds like you found the...
sounds like you found the golden egg.

"S" stands for shock. . .
Or as LRF so politely pointed out in a humorous and roundabout manner, these Eames threads are getting ridiculous. Like pointless on a level beyond tedious.

where's the s?
I can see several other letters and numbers but no "s"....
Maybe just unscrew...

Fair enough points and duly...
Fair enough points and duly noted, "I am an obsessive nut job!" 🙂

blame ray eames...
Rumor has it that Ray stayed up late at night artfully mixing different batches of shock mount color-- black, super black, off black, "dry black"-- and the ever elusive "twig", a dark rust residue color.
She also experimented with a wide variety of cryptic shock mount impressions, cruelly leaving false evidence so that newbies like Crashdesk could never hope to unlock all of the Eames mysteries in a million years-- and people like Lunchbox would end up as simpering piles of frustrated flesh.
Crashdesk, are you aware of a poster named "House Kebab"?
If you are asking all of these detail questions as part of your effort to build that all-inclusive info site you were talking about earlier, you should say so, just to provide a little context.
I have an extremely high tolerance for detail questions (maybe because I teach for a living, and have had to develop a rather ridiculous amount of patience with people who are new to a discipline) Not that I don't go off occasionally...
But at some point, committing an entire new thread to each nuanced question is a bit much.
Maybe you could just have a thread called "Eames Details" and ask all of these questions in one place? ( Just so Lunchbox would have less to rant at when he has had to much to drink)
(And where IS the frigging "S" anyway? I don't see it either.)

PS
I am an "obsessive nut job' too. Totally with you there, Crashdesk.