The last time I tried it I had to put in the SN of the device I wanted to repair in advance to get the part. Maybe they fixed it from then, have not checked.
If you cannot get parts in stock (meaning in advance), you might as well send it to the Apple and not bother with repair shop at all. I also think this is the main reason for making it like that. Display, battery and vibration motor has absolutely no security implications.
I would be very happy to see Apple not screwing with individual repair shops. Don't get me wrong, I'm a huge fan of their HW (be it iPhones or MBPs). But I'm not a fanboy and I'm not going to bend backwards to praise this corporate entity when it is not deserved. If you compare the ease of getting part for Samsung and Apple, it is like night and day.
That System Configuration step is also a middle finger. Having to chat with some support agent just for changing a consumable item like a battery? Or a vibration motor? What the actual f?
edit: Checked and they still want the SN of a target device before selling you anything - even a battery! From the site: The serial number is required and will be shared with Apple. This number must be from the device that is being repaired or you may encounter issues that prevent the completion of the repair.
Yeah, thanks but no thanks.