It should have to deflect the plate some when the center stud is tightened to ensure pressure on the outer gasket. Stack gaskets under the center and it takes pressure off of the outer ring.

I've never seen a gasket used under the center of the plate - a small leak there is meaningless - and the outer rings are at least .150" thick. A smear of silicone on the center block boss should be adequate to seal that joint if it's a concern.