As always you question is very interesting and a very hard one...
I would say yes, because
* Berserk is a special ability, and they are ranked higher, as I see it, than the normal rules...
* you can't berserk if panicked..so as there is no explanation for fear, it should work that way...
I would say no, because
* if it should be like you say, you could give the unit steadfast or immune to fear or something like this...
* it doesn't make sense...first you wet your pants when seing your foe, and then you get angry and kill him cause you wet your pants?
* not being immune to fear for example is a drawback and by using berserk you would ignore this...I don't think it should work this way...
* when you are in fear, you have only one action, you may make another fearcheck, move away or attack another model/unit within range...
just my two cents...
Anomander Rake