Yes, the insulator was standard equipment, except maybe with updraft carbs(?), with a purpose, as posted above. There are two sizes, as posted above.
Here are specific parts from Tim's helpful links:
Jim Carter - earlier insulator plate Jim Carter - later insulator plate Classic Parts - smaller opening Classic Parts - larger opening Even though the shop manuals do not refer to gaskets, a gasket is usually needed between the carburetor and the insulator plate (with properly orientated slots in the gasket to match up with a vacuum port in the base of the carb). A gasket might not be need between the insulator and the intake manifold. You will most likely have to use longer carburetor mounting studs in the intake manifold.
