Yes, that the title of a book he wrote, as well as his eventual end goal for sure.
But he and others (including his son Rand, and Bernie Sanders) have also used the phrase “Audit The Fed” repeatedly as well, for various “Federal Reserve Transparency Acts”[0] over the years, since 2009—including a bipartisan one with Senator Grassley just this past November.
Its "End the Fed"
https://en.wikipedia.org/wiki/End_the_Fed