I noticed that too. I need to check when I get home, but I am pretty sure that the other exclusive items and actual PEs have been made of that composition for a while. I have some non-US Open Premier items and the ones from the past year all have those 3 materials. I do need to double check though.
2011 Wilson Six One 95. Some Ashway Multi. Wilson O dampner.
Nike Vapor 9s: Fed 2012 US Open day. GHOATing, but rocking the bandana more and more.