Chosen Solution
I had my 2018 Touch Bar MacBook Pro top case replaced at an Apple Store due to a faulty keyboard. Were the speakers also replaced?
Yes, the full uppercase is swapped out! Apple collects these uppercase assemblies and ships them to be refitted with new keyboards and battery as well as fully tested, then shipped out as the replacement you got! So… The question is are you having issues with the speakers with your replacement uppercase? If you are I would go back and talk to genius on getting it fixed again in this case they could just replace the speaker(s) alone.
Usually warranty repairs list what was replaced and internal part numbers on the paperwork.
