We know the ending balance was zero. Surely an astute archivist could examine confederate outlays and total them up.
Shadow of the Sentinel: One Man's Quest to Find the Hidden Treasure of the Confederacy
By Warren Getler, Bob Brewer
Interesting book.
As far as I can tell though (from reading some of the reviews), the hoard of gold hidden in the Arkansaw mountains by the KGC was raised after the WBTS ended, rather than before.