Posted 27 December 2011 - 07:50 PM
I'm pretty sure that's not how these codes work, unfortunately.
Back when Music City was opened in December 2008, you could access 41 characters; 38 through regular means, 2 costume characters and Nazotchi. However, after people discovered the codes to access these characters (which supposedly Bandai never intended), they started spreading. Bandai noticed the popularity of sharing codes and decided to make the Nazotchi, Mochatchi and Spotchi codes unusable. I believe that the codes were made unusable around July 2010, upon the Tamatown update to Music City for Tama-Go compatibility.
Dressing up characters also gives the code for the character which had put on the costume, not for the character itself.