Just added scans on the ChipGuide for a new issue M Life Sapphire card from MGM. The new card now has a manufacturer's number on the reverse that's C-00254893S. Haven't seen any other levels with manufacturer numbers so please let me know if you come across any.

Here's a link to the scans of the new card on the ChipGuide
http://themogh.org/cgupdate/cg_showpic.php?pic=../cg_pix/nv/125001.jpg&picr=../cg_pix/nv/125001a.jpg