Chilkat component properties that have a "Date" data type use the Chilkat::SYSTEMTIME class in Ruby. This snippet of code shows how to get the "Date" header field as a string, and as a SYSTEMTIME which allows the date parts to be accessed as integers:
...
print email.getHeaderField("date") + "\n";
lTime = Chilkat::SYSTEMTIME.new()
email.get_LocalDate(lTime);
print lTime.wMonth.to_s() + "/" + lTime.wDay.to_s() + "/" + lTime.wYear.to_s() + "\n"
print lTime.wHour.to_s() + ":" + lTime.wMinute.to_s() + ":" + lTime.wSecond.to_s() + "\n"