Dupe
Thanks Chris but this very same thing was already pointed out last week, right here in an El Reg article:
http://www.reghardware.com/2012/08/10/apple_files_reference_mac_pro_imac_updates/
In comments, it was also already said that the same plist file also lists other models WITH optical drives, so the whole speculation is based on, well, nothing. Two articles about nothing is maybe a bit too much, even for El Reg standards.