Interesting. In Kyle's review of the interior those were absent. You can see at 3:02 of
Ah yes, that's the document that I recall seeing the information in. As it says, the US model ID4 gets a base non-premium audio system for all trims (yay more cost cutting 😒).I see in the pdf linked in ID.4 Trim Differentiation they have those rear speakers specifically crossed out. So, I think that means they removed them from the US version, even if a few of the review cars had them at some point. If so, they may have also downgraded the audio system in the rest of the car.