It seems that the beta version of Facebook for Android (which is, unfortunately, pointed out as being one of the biggest battery hoggers), which is the usual playground for some new features and functionality that might eventually make it to the flagship app, has already adopted the Material Design in a way. While just anybody can become a beta tester, the Material Design overhaul for Facebook beta has not been rolled out to all testers - only a small group of these can hold and behold the Material Design-esque looks of the social network on their good ol' Android devices.
Facebook admits that some time might pass before the app receives Material Design. Until then, you can tease yourself with one of the first screenshots of the new interface. Do you like it?