That is correct. The centering ring is a ring of metal (preferably) but sometimes hard plastic that bridges the difference in the inside diameter of the wheel bore and the outside diameter of the hub. It usually snaps into the inside of the wheel (usually has some kind of friction fit retaining ring built in) and then you can mount the wheel normally.
Take a look here and the pictures of the hub and the little chamfer/shoulder and a diagram of same and a wheel properly machined to manage it. 64.1mm bore. But the shoulder/chamfer carved out to the wider diameter.
Centering ring would allow a wheel to clear that tiny bit of shoulder and then fit snug to 64.1mm bore once past it.
Here is an aftermarket rotor that the hat is thick enough that the shoulder/chamfer does not get exposed (it means the wheels mount 2.25mm further out from the hub essentially).
Upgrading Brake Rotors on Tesla Model 3 – Tesla Model 3 Wiki
And this will explain the rings more clearly and help you envision how they work.
Look at post 1453 by
To3OrNotTo3 of the 2021 Refresh vs 2020 thread. It has pictures of a just delivered Model 3 Performance with the wheel removed. The shoulder/chamfer is clearly visible.