You are correct, Kevin, that there are four to hold the rubber feet. The rubber feet are already mounted to the Kapex when it is shipped.
There is a 4 bolt-and-nut set that is shipped with the UG that hold the base of the Kapex to the UG. There are there are 2 UG mounts that bolt to the Kapex and 2 bolt/nut pairs for each of those mounts (8 pieces total - 4 bolts & 4 nuts). Once the 2 mounts are affixed to the Kapex, it can be mounted to the UG stand without tools, but rather, using the spin/flip mounts that are integral to the system.
Tom