OK, I just checked mine, and they're definitely not flat. And the bolts are definitely not parallel.
But I'm not convinced this is actually wrong:
1) The bolts are fixed as part of the strut assembly. (The rotating top piece, whatever that's called). If these are not parallel, then this means that after the shock tower bowed, it bent all of these bolts too? I don't remember what they looked like when they were off the car (whether they were slightly angled) but I have a hard time believing they are all bent (and if so that would be really bad.
)
2) It makes sense to have a bit of an arch in the top. When you pop the pin and slide the suspension around in the camber slots, the top is moving in a slight arch. If the top of the tower were perfectly flat, the small camber adjustment wouldn't work right.
EDIT: and even if it's not normal, if it gives me some extra negative camber, I'm not sure I care.