Those are two different manifolds shown here. I should mention that there is at least one more, the Doug Nash split manifold which is not shown.
BW, the Gp.IV cars did not notch the decklid and I will add that it appears that I was too quick in notching mine since it APPEARS that the Webers will JUST clear the window opening, but I saved the piece I cut out and it can be dimple welded back in.