If you're wondering which Falcon 9 was test fired, it was the one that ferried the JCSAT communications satellite to orbit back in May. SpaceX didn't use the first rocket it ever relanded (on solid ground), because Elon Musk sees is as a museum piece. The company didn't use the first rocket that successfully touched down on a barge either, because it's too valuable: that's the one the company wants to send back to space.