No manufacturer identifies and tracks each of the thousands of parts that go into every vehicle. It would be an overwhelming task with minimal overall benefit. There may be a few very specific/critical parts that are tracked, but by no means every one. However, knowing when a suspect part was built by a supplier and when that batch was delivered to the asembly plant, they can then normally identify the vehicle build range (and go a little beyond it each way) that would would contain the suspect parts.

I'm guessing that the dealer will be able to identify whether or not the shaft has been properly heat treated by the date code or some other unmistakeable identifying mark on the part. When it comes to a recall there's absolutely no guesswork or judgement call involved!