The fact that the tetragrammaton was included in the Greek text of the OT is a strong basis to accept that the New Testament writers did it as well, especially when quoting from the OT. None of the extant mss/papyri of the NT are earlier than the second/third century CE by which time the tradition of using the nomina sacra had developed.
This proves beyond a shadow of a doubt that the JW's and the Jews are the one true religions.