340 Exhaust Manifolds on Edelbrock Heads

I used a quarter 1/4 header flange on mine.
View attachment 1716321776
Do these require two sets of gaskets? I would imagine you'd need a gasket on both sides of these flanges. Also who makes them, and can you possibly provide a part number? In the meantime... I'm gonna head over to Summit to start poking around. Thanks for the input.