That doesn't cut any mustard with the KJVO. The marginal notes are not "inspired" (except the ones with which they agree).The AV is not ambiguous in Psalm 12:6-7. In the original AV of 1611 the marginal note at verse 7 regarding the word "them" in the text says, "Heb. him, i. euery one of them" making it abundantly clear that people and not words is the antecedent of "them."
HankD