The text has “For example, to specify a date December 12, 2005 …” and then all of the examples use 12 and 1 as if the intention was “to specify a date December 1, 2005”.  I doubt if you want to use December 12 because the specification would be 12 12 2005 but it would be hard to tell the user which 12 is which. :-)

Hope this helps,
Perry