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.
K6.1 95 - NXT Control right now. Wilson O dampner.
Nike CB 2.3: Nadal WTF colorway. GHOATing: Photo Blue, White, Nano Gray, Black.