I got the wheel polishing service. Do I still need to graphite my wheels?

Yes.

Polishing the bores reduces the static friction force – when an object tries to move. Friction is what slows our derby cars down. If we can reduce friction, we will have a faster car.

You will still need a mechanical lube to reduce the kinetic friction forces. Yes you still need to puff the graphite and spin it in as much as you can tolerate. Never too much