No, it has not been widely adopted by Reformed churches, mostly because in many ways it requires beliefs that are seen as matters of liberty of conscience in the older confessions. Ironically, it is also more "ecumenical" than the Reformed confessions in a few areas.
After a cursory review, here are a few significant points of difference with older Reformed standards:
- Article 1 speaks to the superiority of the KJV over other English translations of the Bible
- Article 4 requires belief in literal six-day creation, whereas views like Old Earth Creationism and Framework Theory are often accepted in conservative Reformed circles
- Article 9, on the Sabbath, describes requirements similar to those in the Westminster Standards – more strict than those found in the Three Forms of Unity
- Article 11 eliminates the use of contemporary music in worship services, as well as the recitation of creeds, which are both common (though not ubiquitous) in Reformed circles
- Article 11 does not require infant baptism, as the Westminster Standards do, and does not forbid it, like the London Baptist Confession does.
- Article 12 implies a superiority of pastors over ruling elders, which would break with the "one office" principle.
- Article 13 requires separation from those who don't also separate from the world. So it implies breaking off fellowship with Calvinists who "fraternize" with those who "question" the Bible.
- Article 15 can be read as rejecting partial preterism.
There are relatively few people in conservative Reformed circles who could subscribe to all these statements. And even among those that could, many would see them as matters of liberty of conscience, and thus would not prioritize finding fellowships where these points were affirmed.
Another indicator of the lack of widespread acceptance is the small number of signatories, and perhaps the relatively high percentage of independents and baptists listed also indicates that this document is tailored for a specific subset of Reformed believers. It is certainly not broadly representative of the views of those holding to Reformed theology.