Yes, you might need to, depending on how much the pad raises up. Some just barely rise up enough to clear the vent, so it might be very difficult to stick something down into the vent.
Try this, though - with the neck not installed, press the octave key and the "G" key (ring finger, left hand) - lower vent pad should rise, maybe - but then, wtih your other hand try GENTLY to raise the pad up higher. Depending on the details of the mechanism, it may be that you can GENTLY lift the pad higher than it goes on its own.
The key word here is GENTLY!!!!