Quote:
What created this overdate to appear on 2 different set of obverse dies?
Simple answer is they had two leftover unhardened 1811 dies. Dies were often made in batches and used as needed. Look at the 1800 large cents, there are six different overdated obv dies and all of them were made in 1798. One of them even had the complete 1798 date punched into it. 1798 had a very high mintage (1.84 million, the first US coin to have a mintage over a million.) So dies were being made in large numbers. At the end of the year there were at least seven dies left over, two with full dates and five possibly six just dated 179. In 1799 one of the full dated dies was overdated, and probably one of the 179 dated dies had a 9 punched and used. But coinage in 1799 dropped to just a small number leaving all those other dies onhand at the start of 1800.