Donna,

A Yahoo search for "A/CN.11/L.72"

http://search.yahoo.com/search;_ylt=Apcn3sq3Kg2V1cLh7zPXgu.bvZx4?p=%22A%2FCN.11%2FL.72%22&toggle=1&cop=mss&ei=UTF-8&fr=yfp-t-745

yields results that say no, it's a fake.  Most refernce back to a PolitiFact article that states:

     When we checked with the United Nations, a spokesman declared it a fake.

"I checked the document number on our internal document system, and the reply I got back now was simply, ‘There is no document matching your request,’ said Farhan Haq, associate spokesperson for the Secretary-General. "The document number (A/CN.11/L.72) doesn't conform to our standard system, in any case."

In addition, Haq said, "there is no such body as a ‘Civilian Weapons Confiscation Study Group.’ Nor does the United Nations involve itself in confiscating weapons from member states."

Finally, Haq said, "the use of blue ink, some of the type font and the scanner icon in the bottom right-hand corner are not found in real U.N. documents. So, in several different ways, this document is fake."

http://www.politifact.com/truth-o-meter/statements/2013/aug/12/chain-email/united-nations-document-shared-social-media-says-c/

Ed