USDA Export Requirements for Qatar;

http://www.fsis.usda.gov/regulations_&_policies/Qatar_Requirements/index...

Packaging should have "A statement that the product has been slaughtered according to Islamic principles is required."

A Certificate of Islamic (Halal) Slaughter should be included in the documentation accompanying the exported meat.

I would imagine it's entirely possible that the packaging and certificate could have been removed during the import process, before the meat arrives at the restaurant itself.