R5 heat riser

I'm replacing the gaskets on my intake and exhaust manifolds and heat riser on my R5. One question - their is a gasket and plate on the bottom of the heater box between it and the intake manifold. My parts manual shows the gasket but not a plate. The original gasket had completely rotted away so not sure the order to install these parts. Does the gasket go between the plate and heater or between the plate and intake manifold? Or is this plate an add-on? I'll build another plate if needed as the original plate is pretty warped from heat. Seems like the gasket should go between the plate and heater box to prevent exhaust leakage.

yes there should be a gasket at the mating surfaces.
You can make it out of Exhaust Manifold Gasket material from your local auto parts store or you can see if Olsens Gaskets offers that part.
https://www.olsonsgaskets.com/

Thanks - I got this gasket and the manifold gaskets from Olsen - they were super helpful.