I was under the impression series 1 = 2011 series 2 =2012 etc
However i have just been discussing a 1btc with no misspelling but with 2011 date, apparently a series 3? Is that possible?
https://www.casascius.com/fulllist.txt
The first 11,000 belong to series 1 coins with inkjetted holograms.
The next 1,000 addresses belong to series 2 coins with windowed holograms.
The next 17,000 addresses also belong to series 2 coins, but also start with a prefix that
suggests how the address might be used.
The next 9,900 addresses (prefix 12) are for 2013 0.5 BTC coins or 2013 1 BTC coins.
The next 9,900 addresses (prefix 13) are for 2013 1 BTC coins or 2013 0.5 BTC coins.
Thanks Spike but I don't think that has enough info to know if you can have 2012 series 1 coins or other details like that