Regarding duplicate oem keys

Sometime back i heard that the number written on the keys of the bike can be used to get new keys in case u misplace or loose the key.
I want to know is this a reality or just a fake news as i have lost my Hero Honda Passion's spare key and i dont want to replace the whole lock set or get a duplicate key from the local locksmith.

Please note i still have one key but need both keys as needed by me nd my brother.



curious to know