Not necessarily. A leak in the intake system would allow more air into the engine, the same as opening the throttle. You would then typically adjust (close) the throttle stop to make the engine idle at 700 RPM or so, making the vacuum measure nearly normal. But the thottle might be so far from normal idle position that it could affect fuel flow throught the idle circuit in the carb. This would make it hard to adjust fuel mixture to get a smooth idle.
regards,
Leon
