Yes.
Probably we would first send the invitation to the Auditor General. That's one piece of correspondence that would have to leave. The other one would probably be to either the President of the Treasury Board or the Finance Minister. I'm not sure which one. Budget is under finance, so undoubtedly it would be cc'd to the president—or to the department anyway—to the deputy minister or to the minister.
That would be spelling out exactly what Mr. Whalen and all people would come up with.