The maneuver is more noticeable with the new titanium grid fins (needed because the old aluminum ones caught fire from aerodynamic heating). Not only are they larger, but they use a "sawtooth" leading edge that increases control authority. New: https://twitter.com/elonmusk/status/879065552060260352 Old: http://www.spaceflightinsider.com/wp-content/uploads/2015/12...
They also happen to be the largest titanium forgings in the world. https://forum.nasaspaceflight.com/index.php?topic=42544.340#...
In this case, it's "given enough initial velocity and control authority, even a brick will glide", but the spirit is the same.
A few years back a group of engineers decided to prove this by attaching a number of solid fuel rocket engines to a port-a-potty and launched it to great applause.