How to identify stepper motors?
If the motor has four or more winding connections, then it is likely a stepper. 

If it has four wires, it's a bipolar only stepper. If it has five wires, it's a unipolar only stepper. If it has six or eight wires, it can be used as either.

Another way to find out is to open each motor. If the rotor has a number of ridges at some consistent separation angle, and there are no brushes, then you're likely looking at a stepper motor. (Brushless motors also have no brushes, but don't have the telltale "ridged" stators AFAIK.)