You know what, I was wrong.
Thinking back I couldn’t believe that they would be THAT cheap on this knife so I took it apart, and it does have a separate detent ball.
Mine was quite dirty and the top of the detent ball had worn flat so it was shining and I assumed it was part of the liner. My bad.
The bearings are pocketed into the blade, so if you want to replace them the dimensions will need to be pretty exact.
As for the detent, I suspect that it is steel not ceramic due to the wear, but changing it out may be a possibility. The effect on the flipping action will be hard to predict since there are so many variables there.
Again, sorry Kershaw for maligning the detent. It just feels so soft, mushy, and cheap that I assumed it was worse than it is.