Is This Luke Skywalker's Robotic Hand From Star Wars VII?

Star Wars Episode VII director J.J. Abrams has sent his thanks to fans for their generosity via a handwritten note posted on the Bad Robot Twitter feed.

What's interesting is that the note is being held by a robotic hand. We've heard rumors previously that Luke Skywalker's severed hand would play a role in Star Wars: Episode VII. Could part of Abrams' "thank you" be a tease of things to come?

Star Wars Episode VII opens December 18, 2015.