Hi Bill
In the first picture, it looks like you've labelled the vent nipple as the one that is plumbed to the throttle body. In my set up, the boost signal hose is plumbed to the nipple that is coming off of the part you've got in the middle of that photo. The one you labelled as going to throttle body is vented to the airbox in my '79.
Maybe they changed the WUR over the years?