Note the janky liners on the knife, it's definitely an Emerson!

You can see just about anything you want to see in that pixelated screenshot, and the few seconds of video.
But seriously, the butt of the knife has the same squared off protrusion the specwar has, and we know that NASA has used the specwar in space. The simplest conclusion is that it is the specwar. The other option is that it's a knife that astronaut personally owns, but that's less likely. There's only a certain amount of weight that they can send up to the Space Station at a time, and NASA has to approve everything the astronauts bring with them, even their personal property. If there's a need for a knife up there, it makes more sense that NASA would have one in a toolbox that stays up there, rather than wasting the few ounces of weight to send a new one with every astronaut. That could be another few ounces of food, water, or other experiments, and it costs a lot of fuel to launch even a couple extra ounces.