Did Surratt and Slater know about Harney's Mission?

[L Verge]

"Booth chastised himself, publicly, for not killing Lincoln at the inauguration, but be obeyed orders, then revolted and acted on his own, to gain fame and fortune."

Or, as my grandmother used to repeat from her father, Eli Huntt, "Booth had to do something to save face, since half of Southern Maryland knew that his kidnap plot had failed."