At 1:02 of the linked video you can see the grub screw hole, more or less, pointed straight up. I suspected that but the angle makes it tough to be sure. Thanks for the confirmation.
Interesting way to secure the feet. If it were me, I would check tightness on those grub screws and see how tight they need to be in order to keep the feet in place. A little dab of blue loctite might be in order here, just to be safe?