Can Apple detect a jailbroken iphone, even after restore?

[sup3rsal]

I know it wipes everything out but what bothers me is that there will be some sort of trace left behind..i had once jailbroken my first gen iphone, backed it up and then updated my 3G and it had a custome carrier name.....i droped my phone like many other times a while back and since then the power button on my 3gs wont work properly so i am restoring it and hopping apple wont catch the jailbreak...there is no sign of damage on phone..