Is there an official Spanish Scrabble Dictionary?
Here's a nice picture of a Spanish tileset that I found: http://gtoal.com/wordgames/details/spanish/

That page links through to the FISE webpages (Federacion Internacional de Scrabble en Espanol), where it is claimed that as of 2009:


  El diccionario oficial de Scrabble es la versión 1.0-2003 (edición
  electrónica) del Diccionario de la lengua española de la Real Academia
  Española (DRAE).


Hope that helps your investigations!