I recently heard a radio interview in which the person advocating the position against the KJV-only position, asserted that none of the Greek manuscripts match the Textus Receptus in omitting "his name and" in Revelation 14:1. The KJV, however, follows the Textus Receptus precisely in this place and omits the "his name and" from the text.
I thought this was interesting, so I checked the UBS4 and the NA27. Neither even makes reference to the variant reading. Perhaps that is the reason that the person on the radio assumed that there was no Greek manuscript support for the omission.
However, Tischendorf's 8th Edition identifies at least two manuscripts (P and 1) that omit the phrase. It also appears that the Slavonic version omits the phrase.
Using standard modern textual critical techniques, one would expect that the shorter reading would be preferred, and the longer reading would be dismissed as interpolation. Surprisingly, that's not the case. Instead, the longer reading is preferred by the critical text.
I'm inclined to favor the longer reading myself, because it is easier for me to imagine how the phrase could be omitted than inserted. I find the internal evidence uncompelling. The phrase doesn't have any immediate connection to the remainder of the text.
Revelation 3:12 seems to slightly support the longer reading. Some of the later parts of Revelation also seem to support the longer reading, in that God and the Lamb are clearly united (Revelation 22:1-2). Furthermore, I reject the conventional view that scribes are more likely to add than omit, in fact I tend to believe scribes more likely to accidentally omit. Here there is a reasonable explanation for how P and 1 (and others?) could have omitted the phrase, the Greek phrase is:
τὸ ὄνομα αὐτοῦ καὶ τὸ ὄνομα τοῦ πατρὸς αὐτοῦ
the name his and the name the father his
Notice how the two phrases begin with the same two words, and even end with the same word (although that last word may be the subject for another time). This kind of scenario would make it very easy for a scribe to accidentally lose his place and pick up from the wrong spot in copying out the text, thereby inadvertently omitting the phrase from the copy. This would seem to be a relatively easy explanation for manuscripts P and 1 that would account for the presence of the phrase in the major version (Latin) and the majority of the Greek manuscripts.
Incidentally, one does not find the omitted phrase in any of the TR Bibles, starting with the Tyndale Bible. One does, however, find the phrase in the older Wycliffe Bibles, which were translated from the Vulgate.
What is the bottom line? The person making the claim on the radio was probably wrong. A few Greek manuscripts do contain the variant reading. Nevertheless, the point that the person was trying to make, namely that the support for the variant is weak (miniscule, we'd say, if we were trying to amuse), is correct. Revelation 14:1 represents a verse at which it seems that the KJV might be capable of improvemen, which was the guy's point.