Observe how the rotor shaft will rotate a little as you remove the distributor. This is because the drive gears are usually tapered and as you pull up on the distributor the unmeshing of the gears causes the shaft to turn. Remember when you reinstall the shaft you will need to be off center to the mark you made by a little to compensate for this gear taper. Make sure and disconnect the battery ground cable so the kid doesn't roll the engine over while you're working at the bench. If you forget, and he does, don't dispair.
Some engines have a tang at the bottom of the d-shaft which runs the oil pump.
Make sure this tang engages the pump shaft. If it doesn't then put a little downward pressure on the shaft and then rotate the engine a quarter or half turn. The shaft will then drop into postion. Now that the distributor is in the vise observe the inside condition. If there is oil in it then the bushing or seal at the bottom of the distributor is bad and needs to be replaced.