Yes, some do as an integral part of their design build. Some even offer more than one switch point. Some flow meters do not offer any. It is dependent on the flow meter model.
Here are some rotameter oil flow meter options that also offer an integral switch.
VKG Series - Oil Flow Meter and Switch (up to 175 PSI)
VKM Series - Oil Flow Meter and Switch (up to 5,000 PSI)
VKA Series - OEM Oil Flow Meter (up to 3,600 PSI)