Interesting story. I'm not sure what time frame you reference when speaking of Deputy salaries?
Actually, the were paid (from memory $2.00 to serve a warrant) (Writ) and they were paid 11 cents per mile for themselves and another 11 cents for the person arrested to be transported to Fort Smith. Of course, that was the rules after 1889 until 1896 when the law was changed making the deputy job salaried. The U.S. Marshal that the deputies worked for always took a percentage of the deputies payments.
The deputies, at times, were required to escort those convicted to Federal prison up north to places like Detroit, MI.
Your story on Sam relates closely to what I have in my files.
Looks like you did some good research.