here is the Kidsheart site for the sileighty. they give costs, equipment, colors, date of manufactur (it claims may 1 1998), everything.
http://www.kidsheart.co.jp/sil.htm
interesting note is you could order one with a Nismo LSD installed as an option. this confirms the dealer made theory, as it is clearly stated on the site (if you can read japanese). and if you want it in english, babelfish puts it as "until now, as a new model car it did not exist." and "entrusts vehicle production to the NISSAN related dealer and sells as the new model car."
theres the proof.
edit: on the site they do mention that sileighty "emblems" were made for the glass and rear.