Correct. async/await was first introduced V8 v5.2 but put behind an testing flag. Node.js v7 includes the latest stable version of V8 (v5.4) which was promoted two weeks ago but still has it behind a flag. The current beta version of V8 (v5.5) now has async/await enabled by default. Shortly after V8 v5.5 goes stable, in about 4 weeks, Node.js will update to include it. However, it will most likely be only updated on the v7 branch and not the v6 LTS branch.
Also of note, chakra still has async/await behind a flag as well.