There is no vacuum to the V Boost sensor but the is to the advance unit which I assume you are referring to?
If you are trying to solve a problem then it would be helpful if you gave details.
To answer your question, I don't know as it's not something one would normally check because when testing the sensor you are interested in the output voltage.
I suspect it doesn't matter if there is a degree of 'leakage' as the engine will be maintaining or releasing the vacuum depending on throttle opening?