The KJB translators did not promote modern versions but wrote:

" Truly, good Christian reader, we never thought from the beginning, that we should need to make a new translation, nor yet to make of a bad one a good one (for then the imputation of Sixtus had been true in some sort, that our people had been fed with gall of dragons instead of wine, with whey instead of milk); but to make a good one better, or out of many good ones, one principal good one, not justly to be excepted against."
(Page 16)

The notes never go against the KJB or the KJB Only position at all.

The KJB translators simply said they wanted to make a good one better, and out of many translations one principle good one. Nothing about for or against KJB Only in the above quote from Page 16 of the KJB Preface.

(Extra note: the KJB only position is use KJB only & this position is for English speakers & readers only; everybody else should read the Bible in their own langauge that they speak and read in)

𝕋𝕙𝕖 ℝ𝕖𝕒𝕝 𝕂𝕚𝕟𝕘 𝕁𝕒𝕞𝕖𝕤 𝕀 & ℭ𝔳𝔠𝔨𝔱𝔥𝔬𝔩𝔦𝔠𝔦𝔰𝔪