Are all the pump flanges the same on each and every pump?

With this is it is the same as with the pump shafts.  The standard pumps are clamped on the flange of the motor with a stainless steel clamp. But with the pumps used on espresso machines from Gruppo Cimbali you have pumps which are bolted to the flange of the motor. This can be a 3 hole flange, or a 2 bolt model.