Yes, but the term 'back-emf' is used to mean several things. Firstly, any motor creates a back-emf whcih resists the current that drives the motor and is a result of the changing, rotating, magnetic field - this is the voltage generated in the windings by the motion and would be apparent if the motor was driven by the inertial load (bad in a CNC machine because the load should be under control at all times!). Secondly, with a pulsed stepping current there is an induced voltage that occurs whenever the current is switched off and is a result of the magnetic field collapsing - it has nothing to do with the motion of the motor as the same back-emf is observed in relays and solenoids and ignition coils. It is the latter rather than the former that is the issue discussed above.