Exhaust manifold gaskets needed on 340?

Question: Should a '73 340 have gaskets installed on the exhaust manifolds? I just had my engine rebuilt, and I don't recall there being gaskets in place before the engine was torn down. My shop tells me that some engines came from the factory with exhaust manifold gaskets, and some did not. He seems to think they should be installed on my car.

What's the correct way to go?

Thanks