Oil filter adaptor gaskets?

Hello FABO friends,

This is my first SBM and I am curious about the adaptor that the oil filter screws into. There appeared to be two very worn gaskets on either side of this large bolt. One was under the head of the bolt and the other was on the inside up against this flat area. I have not been able to find such a gasket on websites such as Classic Industries and so I turning to my FABO friends for guidance.

Any insight or assistance would be greatly appreciated!