It is reported that FoxConn has a capacity of 150,000 units/day. There is speculation that production began in July or early August. Let's assume it started in mid-July.
July - 2,550,000
August - 4,650,000
September - 1,950,000
Total = 9,150,000
By end of business today, FoxConn would have produced 600,000 units since Friday.
Apple claims sales of 2 million units in first 24 hours. We have no idea how many units were allotted to carriers, retailers, and Apple brick and mortar stores. Also, keep in mind that the iPhone 5 was launched in 9 countries.
Apple - 383 retail stores.
Best Buy ~1,500 stores
Target 1,700 stores
Wal-Mart 4,700 stores (United States)
Now add retail stores and carriers in the other 8 launch countries.