Good job! I've been wanting to make this model as well.

A good close up of the head is here (zoom in):
http://www.hammacher.com/publish/10921.asp?cm_ven=CJ&cm_pla=1492714&cm_ite=Hammacher+Schlemmer+logo&cm_cat=1414665#

Modeling Tutorial with links to photos of Robby:
http://www.clydesight.com/brRobby/contents.html

Detail photo of head interior construction. Click on Restoration tab, then Details:
http://www.the-robotman.com/

Keep us posted !

Ed