I stayed at the Cosmopolitan this summer and was upgraded to a suite and received free breakfast each day. I did eventually receive the 500 pt amenity, though it took some work chasing all the points for the stay.
I just returned from an award stay at El Monte Sagrado in Taos. They were sold out all week, so I got the 1BR suite I reserved. I did receive my chosen amenity - 2 sodas and a very nice cheese/fruit/crackers plate as well as a coupon for $10 off breakfast for each morning of my stay.
Having opened in 12/2010 and in 2003 with a doubling of rooms in 2007, respectively, I can't agree that Autographs tend to be old.