I am becoming less confident there will be much movement on shipping dates, though I hope I am wrong. Here's why:
The WSJ reported that Foxconn, the only Chinese manufacturer making the iPhone, was producing about 140,000 6+ a day. That is 980,000 a week. Many who ordered 6+ on the 12th shortly after preorders began were receiving a 10/3 or 10/10 ship date, so I would figure that Apple had few 6+ they were able to ship.
Apple sold 4 million iPhones on the 12th. If we assume there was a 50-50 split in sales, that implies 2 million 6+. That is about two weeks of production, or a 10/3 ship date. While there may be some movement on the more recent orders whose ship dates are late October (assuming a faster production rate due to more workers, greater efficiency and more supply of the larger glass), I would suspect any movement will not be dramatic.