Once you pull out distributor and the oil pump drive shaft, which has the gear pinned to it, you can see the cast in gear on the cam with a flashlight pretty easily. Have someone turn the engine over for you while you look and be sure to check the entire circumference of the gear which will require turning the engine over twice.
If either of the gears are very badly damaged, you may need to pull the pan or engine as you don't want all that metal running through your engine.