However, Windows Phone Central has now come across new documentation circulating within AT&T that does indeed confirm the date of October 21 st as an important day for the upcoming Nokia flagship phone. This is not the same info that presumably BGR saw (or was told) due to its recency.

The technology site BGR recently cited Sunday, October 21 st as the launch date for the Nokia Lumia 920 . At the time, we gave a low rating to the rumor due to two reasons: BGR’s rumor track record (52% on Tracour) and the fact that the date conflicts with other word-of-mouth bits of information.

The language in the documentation clearly uses the word "launch" when discussing the Lumia 920, however there are mitigating circumstances that still makes it hard for us to believe. If we had to play it conservatively, we still may be getting the preorder date.

Unfortunately, due to our agreement with our source, we cannot share the contents of the message/documentation nor whom it was from, but be assured that we know that information and we are confident in its accuracy. Our source of the internal AT&T material had earlier confirmed the Mango-update dates for Windows Phone, which turned out to be very accurate. For that reason, we impart a high level of trust in this knowledge.

Could Microsoft, Nokia and AT&T be planning an October surprise?

We still have reservations about this date only because Microsoft is reportedly not set to unveil all of Windows Phone 8 until the end of October and most OEMs we have spoken with are sticking with their “early November” timeframe for release of new hardware. Just as we originally reported, that gives us pause.

However, seeing as Windows Phone 8 OS has been RTM’d this past weekend, that would give Nokia and AT&T just over a month to finish testing the Lumia 920—testing for which we believe has already been underway in a preliminary fashion. In addition, there is near universal agreement that Nokia (and Microsoft) need to get this flagship phone out sooner than later, especially with the iPhone 5 set to launch at any moment.

Could AT&T, Nokia and Microsoft be planning an October surprise to win-back some positive media coverage and cut into the iPhone 5?

Had we not seen the origins of this internal AT&T information, we would be hesitant to post this, but due to the seniority within the company of the source material and its recency, we have little reason to doubt its authenticity.

We'll keep you posted of any further developments.