It looks promising, but the demos still seem like the gun is being handled in a somewhat "rigid" pose. Maybe that's just his play style, but it kind of sends the message that performance will not be the same if the gun loses it's points of reference between shots, or if it's not held perfectly vertical.
The other thing I don't quite understand is why the necessity for the border. There would be literally no difference between doing things this way, and placing an IR LED marker at somewhere close to each corner of the screen and storing a calibration value. A line between two points of reference is still a line, whether or not it's visible to the player. The only possible benefit would be the ability to track closer to the screen, if (and only if) the code was very adept at tracking a partiality of the reference, but at the distance it is being demoed, this doesn't seem to be the case?
Unless this gun is absolutely perfect (something of which I am a bit skeptical) the demos are showing some cherry-picked footage, which makes it difficult to truly assess it's real-world performance. Demonstrated failures are often more telling than just the successes.