It Makes a Difference to the Sheep

Asks Tyler Cowen (quoting Jagdish Bhagwati):

Once, Mrs Joan Robinson, my radical teacher at Cambridge University, and Professor Gus Ranis of Yale University, a 'neo-liberal' economist, were observed agreeing with each other that Korea had been a great success. The paradox was resolved when it turned out that Mrs Robinson was talking about North Korea and Professor Ranis about South Korea!

I wonder when this conversation took place. I presume some time before 1994.