Yes, if it's a grinding sound, it's almost always the ring gear teeth. The engine will usually stop in 2 places (4 for a V8) unless you force it to stop with the clutch. That's where the wear will be.

If it is whirring, zinging sound, suspect the starter itself not disengaging quickly from the started engine.

Both can be can cause by bad starter-flywheel alignment, for example if the starter bolt flange wasn't machined right. Never seen this happen with a Datsun though.