No it doesnt mean that is what piston is in your motor. They can refer to an engine package in many different ways. it usually isnt a "true" advertised cc. Example would be a psi 425 honda, its really a 416, or a 370 honda, which is usually a 360-380. Best way to tell is to look at the crown of the piston and in the part number on the top center will be the bore size.