As a highschooler hearing back from UCs and CSUs at the moment, this is true from the start. The UCs are magnitudes harder to get in to vs the CSUs, and are therefore more prestigious.

However, that does depend on the CSU. Cal Poly is highly regarded (engineering-wise), while UC Merced or Riverside are often held at a "lower tier".

Anecdotally, a lot of people hold Chico at the bottom, and Berkeley/Cal at the top of CA public schools.