Suggest you may get a transient increase in Ng and T4 while the horn would sound as the Nr decayed. We teach to enter auto and reduce throttle to idle (not sure that the governor would maintain normal tail rotor rpm if not driving the main rotor) then carry out an EOL. Could be difficult to differenciate between this and a governor run down as after the initial (and only possible) rise in N1, the N1 would come down to around the idle figure.