Your question sentence that starts with "does" is correct. The answer to it yes
The vent line on top of the wastegate is no longer going to be vented to atmospheric pressure after you hook up the regulator correctly.
The regulator will be feeding the top fitting and top side of the internal diaphram a lower adjustable portion of the entire boost pressure from the intercooler end tank that is currently and will still be going to the bottom fitting on the wastegate.
When it's installed the regulator makes it so you can adjust the pressure differential between the bottom and top side of the rubber spring loaded diaphram inside the wastegate.
If the regulator knob is accidentally turned clockwise all the way the same amount of boost air pressure would be going to the bottom and top sides of the diaphram equalizing the pressure differential and the wastegate would never open...
Car would accelerate really fast for a moment and then kapow.. woop$.