All Starlink satellites have been launched via ridesharing missions, with ~60 satellites per launch (and sometimes with satellites from other companies!).
Actually aside from the first couple of Starlink test units, it has been the other way around. SpaceX launches dedicated Starlink missions on a regular cadence using previously flown boosters, and offsets the cost somewhat by offering rideshare opportunities. There will be 60 Starlink satellites per launch, but sometimes less if they find a rideshare.
The ridesharing program is what SpaceX offers to outsiders, but the concept of rideshared rocket is whenever a rocket ferries multiple satellites to save cost.