For KJV, No. Against Sinaiticus, Yes.

I know JW's love Sinaiticus.

I just saw a video by David W. Daniels. It was against Sinaiticus.* I then was intending to leave a comment there, but put it here instead:

I believe good things about Alexandrians, and about the "seven extra books".

I believe Sinaiticus and Vaticanus, if genuine, are genuinely made by heretics back then, and therefore laid aside.

So, using Sinaiticus and Vaticanus to take away verses would be a bad thing even if you totally do trust the LXX tradition.

I am far less impressed by Tischendorf.**

A Trinity affirming verse out of the one or both. And Tischendorf's mentor, Georg Benedikt Winer,*** seems to have been anti-Trinitarian.

Meanwhile, I am Catholic, and I have argued the Bible identifies its number of books as 73 overall.° Not in a way which would have been obvious then, but one which is obvious now that we have English miles and even more modern kilometers. Maybe you'd like to take a book at David W. Daniels' book.°° It reads nice in the sample:

So, I don't trust Jack Chick's The Death Cookie one bit. But just because David W. Daniels had bad judgement on that one, apparently, doesn't mean I have to mistrust him on his own research./HGL

* https://www.youtube.com/watch?v=OVjOhDJ5HKo
** https://en.wikipedia.org/wiki/Constantin_von_Tischendorf
*** https://en.wikipedia.org/wiki/Georg_Benedikt_Winer
° Does the Bible Say How Many Books It Has?
°° Who Faked the "World's Oldest Bible"?