It's more likely that the KJV is public domain; so, all sales if produced solely by RHB, go back to RHB. Which is still kind of odd, since I think there are now a couple of professional (meaning professionally translated by teams of scholars) public-domain contemporary translations as well they could use. What steers me away from it, is I thought it was annotated with past Reformed commentators, but instead, I think it is all from modern teachers. I could be wrong on this though.
We have students from Puritan Reformed Theological Seminary here who can correct me if I'm wrong, but as far as I know, the Heritage Reformed Congregations are officially a KJV denomination so it would be a major surprise to me if they **DIDN'T** use the KJV as their base text. In a previous generation that would have been normal in conservative circles, including conservative Reformed circles, with the Christian Reformed Church being the one major exception to that rule.
There had been **REALLY** strong opposition in conservative circles to the creation of the RSV, most of which was legitimate due to the translation committee including liberals and being sponsored by the National Council of Churches. Because the CRC was still mostly a Dutch immigrant denomination there had been openness, even from a very early date, to alternatives to the KJV because of difficulties faced by people for whom English was a second language trying to understand the KJV. It wasn't a big surprise that the CRC and a number of Calvin Seminary professors took the lead in creating the committee that eventually produced the NIV as an evangelical alternative to the RSV that would provide an option for those who struggled with the KJV's older English, or had problems with the Textus Receptus, but objected to the RSV's translation principles.
The problem is that the NIV, by adopting a "dynamic equivalence" principle of translation, and then playing footsie with feminist issues in later revision efforts, made itself unacceptable to a lot of people it was intended to reach. Today we have a number of other alternative translations that provide an option that is closer to the text than the NIV but doesn't have the RSV's problems of liberalism, and we also have the NKJV for people who want to stick with the Textus Receptus.
Most of that didn't exist a generation or two ago so there used be a lot more support for the KJV in Reformed circles than there is today.
I remember an elder from the Crescent Street congregation (Dr. Beeke's church), back in the 1990s when it was still in the NRC, saying at a NRC synod meeting that the synod had no authority to do certain things, and he cited amending the church order and changing the KJV to NIV as examples of things the synod had no authority to do. Now of course that's one speech by one man, but he made his speech with the assumption that everybody on the floor of synod would agree with him, and nobody did disagree with him.
At least back then, that shows how much the use of the KJV was assumed in those circles.
Again, I'm not KJV only. I don't want to get into those debates. Just trying to explain the context -- Dr. Beeke works in a context where some things are assumed, and a lot of other conservative Reformed denominations used to share those assumptions.
Put bluntly, if the only viable options out there were the KJV or RSV, what would most Puritan Board people choose? Or if the only viable options were KJV, RSV or NIV?
I studied under some of the NIV translators at Calvin. I am the first one to say that my Greek today is close to zero, and my Hebrew never was very good. I'm the wrong person to be evaluating the fidelity to the text of modern biblical translations. I'll leave to the people who are experts on Greek and Hebrew to comment on those subjects.
But I sat in class and listened to those professors explaining the principles behind the NIV, and as a person who used to be a big fan of the NIV (my church at that time used the RSV and I knew its liberal problems), I was horrified with what I was hearing from my professors on their principles of Bible translation. Whatever Bible translation we're using, we need to understand its underlying presuppositions. I wouldn't tolerate the translator of a secular contract in private business using "dynamic equivalence" for a business deal with legal consequences, and we have every right to expect greater fidelity to the actual words of the inerrant Word than we can expect from the translators of a business contract.