Do you think you could lead a Roman Catholic to the Lord by using their RC bible?
There are saved Catholics. Just like in protestant churches, some members are saved and some are not. Catholics lead other Catholics, non-believers, and even Protestants to Christ, and of course with their own Bible. As is mentioned earlier, the KJV originally contained the apocrypha. At times I have attended churches, Catholic and Protestant, that used Bibles that included the apocrypha. I prefer the KJV, and at one time owned a KJV with an apocrypha.
Before the pandemic, I attended a Catholic chapel almost every day. The chapel was next to my post office in a large shopping/office complex that included hotels and a convention center. I used to rush home from college and dump my bag and books before chapel, if I had time. If not, I got off the subway and went straight to chapel. Then I got my mail, just as the post-office was closing, then grabbed my supper at the grocery store, and finally went home to eat and do my homework. That was my routine and it was a good one.
I was baptised Catholic as a infant, but did my first communion at an Episcopal church, was saved in a Pentacostal church, confirmed at a Lutheran church, and was later rebaptised in a Baptist church, and attended all sorts of other places in between and afterwards, including Charismatic Catholic meetings with my very-saved step-grandmother when I was a pre-teen. There were saved and unsaved people in every church.
That Catholic chapel was a fascinating place, that drew people from all over the world and all economic classes. You would see doctors from a nearby hospital still in their scrubs, very very rich people, homeless people, and immigrants from the nearby hotel kitchens, visitors from Asia and almost anybody else you could imagine. I will never forget a young skinny Hispanic man in an apron with flour on it and bright red sneakers, kneeling behind one of the last back pews, praying hard about something, before he dashed back to the kitchen to finish his work. The world came to that chapel. The church was there, all of it historically and geographically.
I miss my old life so much, and the Catholic chapel is one of the things I miss most. My old neighborhood is a shell of what it was, and the building I lived in has been sold. That area will never go back to what it was. More and more of the people i know are leaving as they figure that out and leave voluntarily, or are forced out.
The Catholic chapel was there when I hit rock bottom, and didn't have my faith back yet, but was ready to listen. I needed a place to go DAILY and sometimes twice a day. It was the Catholic church that was there, every few hours, and leaving the doors open for prayer between.
I prefer the KJV, with or without the apocrypha.