This is a very crude diagram of my 940 turbo exhaust flange. Although a southern car, I don't know if this is the original front pipe. On my 240, both the cat and down pipe flange were identical, allowing the use of a gasket. In the case of the 940, as seen in this diagram, It would be difficult to envision.
That's not to say that one doesn't exist. At Advance Auto they had a diagram for a gasket that resembled a short pipe that protruded into both the cat and the front pipe. In the center of this cylindrical gasket was a ridge that may have mated the two flanges. The diagram was too crude to justify the 16 dollars. and disturb a now non leaking system.