Ok, so not quite. In the first picture, there is one nipple on the bottom of the intake that has almost no hose on it. That one goes to the vacuum tree attached to the fender. The other vacuum nipple on the bottom of the intake has quite a bit of hose still on it. That hose goes to a T at the back of the intake where that giant screw in piece is, and then continues on to the PCV valve. So it gets vacuum from both the bottom of the intake, and the back of the collection portion of the manifold to suck from the PCV valve. No clue why it's like that. I wouldn't put too much effort into it honestly. Make sure there is vacuum going to the tree, and vacuum going to the PCV valve. If you need to cap a nipple, just go ahead and do it. You are going to need an aftermarket manifold for your 347, and it won't be setup like that, so don't over think it. Obviously you will need new hoses. Just get bulk 3/8" fuel hose from the parts store for 78cents/ft or whatever. It will work fine.
Kurt