I'm fairly certain that both Wu and Heller are knowledgeable about Coase. The whole Law and Economics movement, with Guido Calabresi and Richard Posner in the vanguard, has all but canonized Coase.

The real question then is how Heller attempts to differentiate "anti-commons" from "transaction costs." Wu doesn't follow up the witty conference anecdote with any account from Heller - either from the book or through personal correspondence between Wu and the author - of how his contribution is markedly different.

As for the putative mistake of Wu ostensibly crediting Heller with something "ground-breaking," I think we should be mindful that most titles are the work of editors, not authors. I'd really be surprised if Wu thought - even in jest - that Heller's contributions were anything on the level of Marx - or any notable economist for that matter. (And let's not get into a debate about whether Marx was in fact an economist. I know there are at least a few of you so inclined to quibble).