In theory, you should see some gains... In practice, that's another thing all together.
I installed ceramic bearings in my stock wheels a few years ago. Zip, nada, nothing gained at the track (the bike was easier to push, though
). Later down the road, I replaced the stock wheels (with ceramic bearings still in them) with my Carrozerria wheels that are on the bike now. Again, ZERO gains netted at the track.
The person who bought my old wheels to replace his saw no gain from the ceramic bearings either, and his wheel bearings on his old wheels were SHOT.