I don't know for certain but from what I know of Johnson he was more than capable of fistacuffs. Given the circumstances and the feelings among Tennessee Unionsts I would not be suprised. I have read extensively the works of these Federalists. Judge Oliver Preston Temple, U S Congressman, Tennessee post war supreme court justice, Thomas Amos Rogers Nelson,(Nelson was Johnson's defence attorney during impeachment), Congressman Horace Mayarnd, Parson Brownlow (he despised Johnson) and several others of the time and until today with Dennis Brooke's post. I have never heard of the Buell incident.
The fact that the information comes from a private letter
lends credence to the truth of the tale. It seems to me that if such events took place. it was only shared with those with first hand knowlege. I think they would be supressed for fear that it have an adverse effect on morale. Rather like when Bragg's generals mutinyed at Chattanooga.