For clarification, Franklin, you are stating that you gave Kathleen Kilpatrick an April, 1865 contemporary newspaper that states per you quote:
"Three days before President Jefferson Davis left Richmond, Provost Marshall and high member of the KGC, Sam McCubbin, took $8 Million in gold specie by train out of Richmond to some point South".
In the Richmond Daily Dispatch, February 13, 1864, lists Samuel McCubbin as Confederate Chief of Police in Richmond, involved in the arrest of Richmond embalmer, who, for a price, was aiding Confederate deserters escape to the North.
Other news articles in the Richmond Daily Dispatch and Richmond Sentinel which contains the same story-
www.bluegreyreview.com/2014/02/14/stung-on-the-underground-railroad/
From February 1864 to April 2, 1865 have several articles of McCubbin's duties as either Chief of Police or Captain of Police, rounding up Confederate deserters and returning them to their units or to the gallows.
McCubbin is never referred to as "Provost Marshall and high member of the KGC" in these newspapers, nor is that McCubbin "took $8 Million in gold specie by train out of Richmond"
Then McCubbin is mention in that Monday May 1, 1865 NEW YORK TIMES article reporting to the Union Provost Marshall of Richmond on the Saturday before, interrogated of his activities which involved chasing deserters up until Lee's surrender.
Without proof of an actual newspaper article, with all the jumbled information, this McCubbin treasure story has the appearance of originating from a pulp treasure magazine that mentions "according to a April 1865 newspaper article" as its source for the story.