But when are you really going to overboost the engine? You are using autothrottle and the engine will be commanded to stay within limits. We had a situation a while back with a failed SAARU using the MEL. After start, as expected, both EEC's were inop. Full thrust takeoffs for both flights at light weights but no other real worries.
Lets see..manual go around,AT is OFF,PF firewalls it ...go around thrust is 98% (temp/elevation) and 100 % is set.Thats an over "boost" , over thrust if you prefer.
As written above for an overspeed...n1 and or N2 briefly overshot until the EEC reduces the fuel or the overspeed governor takes over.