Yes there is a password for it.
For Japanese
The password for Lucario was made available in the Weekly Famitsu issue released December 22, 2011.--Bulbapedia
For English, French, German, Italian, Spanish
> The password for this promotion came with specially marked copies of Pokémon Black and White available in participating American Target stores starting January 15. Copies with the password were limited.--Bulbapedia
Source:
http://bulbapedia.bulbagarden.net/wiki/List_of_Pokémon_Global_Link_promotions#Pok.C3.A9mon
Lucario is the last pokemon to look.
