Unfortunately, I can report this wasn't the case for me. Same problem, dead pixels on a 12.9" 5th Gen.
I went through Apple Support, booked a Genius Bar appointment, I posted a thread before I saw this, my entire area has zero stock for replacement units. The guy even told me if he replaced it, I would only get a 3 month warranty with the new one.
I returned it, now I have to search to find one.