Not sure how they are classified, but here's a photo.
At one time (up through the end of 2011), on a site called G503.com, in the infancy of GMTK collecting (each GMTK had a 41-W-2615 midget socket set, among about a hundred other pieces), the "Conventional Wisdom" on WW midget sets was that all 5-hinge boxes were wartime and all 6-hinge boxes were postwar. Until sets with wartime construction, markings, configuration and finish started showing up in 6-hinge boxes. Mine was actually the first. Then the roof caved in. The CW changed to 5-hinge early, 6-hinge late and postwar, depending on the other factors (construction, markings, configuration and finish). Lately, though, this original pioneer is less definitive about any of the CW he was instrumental in developing.
Looking through, this is a complete 3100A
Yes, perhaps, but the CW would say your pieces don't match your box.
I'll explain...
Because of the finish (cad) and the markings (Long W) on the sockets, and their number and configuration (sizes and broachings), there was a time when the CW would say you have a
complete early- to mid-war wartime commercial 3100A set, or a
partial early- to mid-war wartime GMTK set (missing its ratchet, sliding tee, and extension), inside a 6-hinge
postwar box. Meaning, it looks like a PO may have taken the early- to mid-war pieces and put them inside a postwar box that the pieces were not original to.
Then there was a time, after 2012, when the CW on these would say you have a
complete early- to mid-war wartime commercial 3100A set, a
partial early- to mid-war wartime GMTK set (missing its ratchet, sliding tee, and extension), inside a 6-hinge
late war box. Meaning, it looks like a PO may have taken the early- to mid-war pieces and put them inside a late war box that the pieces were not original to. And some collectors would say that right now. Such is the strength of the cad=early, 5-hinge=early, and black ox/6-hinge=late sequencing CW.
Lately, as I mentioned, I am not as sure of the CW dating these sets too strictly and definitively based on construction, markings, configuration, finish, and hinge elements as I once was. I have seen enough anomalies and we just don't have enough provenance on any of the sets being original to each other or the boxes to be too strict with sequencing, in my opinion. Other collectors have disagreed with me on that. I am not trying to persuade them or anyone else to agree with me. And I am equally un-persuadable. So there is no reason to go into it.
But it does make me open to other possibilities...
Your set could be a postwar 3100A set inside its original postwar 3100A box, exactly as you have identified for yourself. Many mfgrs used cadmium before and after the war as a price point line finish. It was not only a wartime finish. And it's possible WW was using old stock.
Or, it could be a complete late war GMTK set (no rat, tee, or extension specified) that does not adhere to the late war all 6-point specs or the cad/Long W=early sequence, or it adheres to some later war or even postwar spec we don't have, in its original late war 6-hinge box.
Or, it could simply be an early- to mid-war commercial 3100A set, or a partial GMTK set (missing its ratchet, tee, and extension), exactly as the CW-adherents would say, but inside its original 6-hinge box, defying the CW on the strict 5=early 6=late hinge element sequence. (What if they got them from multiple suppliers? What if they got them from the same suppliers using multiple suppliers for hinges? etc)
What is the most plausible?
Go with "transitional"! That always works!
Or even more broadly, a wartime set in a wartime box.
...and figuring something out with the case.
Does it look like it's been re-painted? I don't see anything under that kelly green but steel. I suppose it's possible someone completely stripped the original finish, and re-painted it that color. As I and others mentioned on the 'Midget' thread when you first posted this there, and as you can probably see from examples, there was a darker almost olive green, a much more common darker but truer (not olive) green, and then red (postwar).