halacha - If a Mesorah for letter pronunciation is rediscovered, would we have to change our pronunciations?

Let's say that someone finds some historical evidence that a particular system of pronunciations, whether it be currently extant or not, is the one which Klal Yisrael used at the time of Kabalas HaTorah. Let's further assume that this evidence is absolutely indisputable and everyone from all sects of Judaism are able to agree on its accuracy.¹

Would we all have to change our pronunciations accordingly? For instance, if the evidence supports, say, the Yemenite tradition, will we all have to begin saying Berachos and leining and whatnot with that tradition? Or does the minhag that has been accepted by the various communities override any evidence to the contrary? Would it depend on the halacha it's being applied to (ex. Torah requirements like saying Shema would have to change, but you can say Rabbinic berachos however you want)?

^{1What would such evidence be? I don't know. You should be able to tell it's a theoretical question just from the fact that everyone is able to agree on its accuracy.}