To a point, yes. The bypass valve starts closing around 1/3-1/2 throttle, and it closes progressively all the way to WOT. I've found that at roughly 30-35% throttle (near 6mmHg vacuum), I can hear the bypass valve start whistling a bit, and the ECU starts dumping fuel (A/F drops to 11.5-13:1). Past that, boost is dependent on the amount of throttle.
The bypass valve is underneath the front part of the blower casing. It's really only visible from the bottom.
edit: The above info is from watching my vacuum/boost gauge, and the Brockway R920's A/F reading (straight off the OBD2 bus).
Bookmarks