MOPED ARMY

I'm going to check out a Puch Maxi tomorrow (this will be my first moped), and I'm wondering if anyone knows of any external indicators of the moped's horsepower. I know that one can determine horsepower by looking at the intake, thickness of the head gasket, etc., but I figure I shouldn't rely on the possibility of the current owner letting me take the engine apart in order to determine horsepower. I'd be happy with it if it's a 1.5 or 2, but it seems like improving the speed of a 1 horsepower engine is a much more involved a process (though do correct me if I'm wrong).