We know that the OT text was preserved through the Mesoretic line, and that the true reading was not always in the main reading, but in the additional notes. So as such the Masoretic Text as a whole has places where there is a choice between readings.

In conjunction with this, there are various Hebrew Texts, as well as the Vulgate Text, LXX Text, etc. The Old Testament was in Hebrew, but finding the correct text in the Hebrew could also have witness to it from other versions as well. However, I take it that where the LXX Text differed from the Mesoretic Text, that the King James Bible does not follow the LXX.

But it is translation where the LXX, Vulgate and so on become really helpful, because the translators knew that by consulting a variety of translations, they would profit in finding out the sense, that is, how to translate the Hebrew. The important point here is that they were choosing a Hebrew text and translating the Hebrew into English.