I wasn't around in 1942 to tell you from personal experience, but here's my understanding:
While the Judge was alive, the expectation was that the war that was ongoing (World War II) was going to escalate right into Armageddon. The Judge died in early 1942 and Nathan Knorr took over (with Freddy Franz as head theologian :P). A very short time prior to these events, there had also been a major change with regard to the war: the United States had entered it. This created a very different outlook for the future, and attention came to be focused on the likelihood that the war would end and be followed by (hopefully) world peace. So, yes, Knorr's talk presented "new light" on the subject in accord with the changed situation.
If I had to make a bet, I'd guess that there was already some talk going around of a revival of the League of Nations, though possibly not in the form of a completely different organization, as actually happened. The League still existed officially at that time, but was obviously ineffective in its peacekeeping mission, given that most of the world was embroiled in war. When a glimmer of hope for peace appeared on the horizon, however, it was only natural to speculate that the LoN (or something very much like it) might have a role to play in the politics of the coming peaceful world.
So, did the WTS get it right? In a sense, I guess you could say so, but not in a way that couldn't have been duplicated by anyone at the time who was reading the newspapers and thinking a bit about the future. I suspect that someone with more time on their hands than I have could probably root around and find quotations from non-JW sources at the time predicting the same thing. If God were really giving them their information, they should have known that the war would end BEFORE events in the world made it obvious to ordinary observers.
Even if we did have to acknowledge that they got one right, it would be meaningless given the overwhelming number they have gotten wrong. The JW's qualify as a bona fide false prophet in the manner of Deuteronomy 18:20-22. They have repeatedly spoken in God's name ("Jehovah's prophetic word," "the Creator's promise," "God's dates, not ours") and their predictions have failed to come to pass. One failed prediction is sufficient to identify a false prophet; one correct prediction does not make one a true prophet.