My buddy has his motor together (396)..it has new everything..including crane roller tip rockers. With the valve covers off, I noticed that (viewed from the sides of the motor, looking toward the carb) that the roller tips are not all evenly centered on the valve stems..not sure if this is normal, or whether there is a problem somewhere.

When I say 'not centered' I mean that the roller tip looks to be off center of the valve stem (front to back of the motor) when viewed from the side of the car.

Is this normal, or is there some adjustment that needs to be made?

If they are off slightly it won't hurt a thing.
If they are off to the point of seeing the top of the valve stem at the edge of the roller you should "adjust" the guideplates.
You may be able to just loosen them & split the difference between in & ex or you may need to "tweak" the guideplate itself.
Worst case, you cut the plates, adjust each one individually & then weld the plates back together.
This is very rare, normally moving the plates or a slight "tweaking" will center them. ;)