Are the lower intake manifolds interchangeable between 1997 & 1999 5.0L on 1999 Mercury Mountaineer

97 has a whole top center and 99 is blank between the 8 input orifices.

Asked by for the 1999 Mercury Mountaineer
Part numbers differ, so I would advise not trying to switch....whats wrong with your intake manifold?
Broke the far left corner trying to chisel the head off a stripped bolt. Already replaced with the 97 manifold but had to plug the center hole due to exhaust leak(hole had to be to exhaust because with out plugging it sounded like the exhaust manifold was loose)Used a hardened rubber plug from Nissan rearend. If for some reason it does not hold I'll replace manifold.
Thanks for getting back.