The original manuscript is not extant here. In the printer’s manuscript, Oliver Cowdery’s text, as he initially wrote it, lacked a subject in the final main clause. The subject pronoun they was later supralinearly inserted with heavier and darker ink flow. The hand does not quite look like Oliver’s. One possibility is that the they was inserted by John Gilbert, the 1830 typesetter, especially since this inserted word looks somewhat like the of that Gilbert supralinearly inserted on the previous page of 𝓟 (see line 26 on page 85 of 𝓟). If the correction here in 2 Nephi 27:6 is Gilbert’s, then this example provides a clear case of editing on the part of the typesetter. Such editing by the 1830 typesetter did not occur very often. For another possible example of his editing, see 2 Nephi 10:3 (there Gilbert was apparently the one who deleted a redundant “that he”).
Obviously, some emendation seems necessary in 2 Nephi 27:6 since the text does not intend to say that “the Lord God … shall be the words of them”. The most reasonable conjecture is that the subject pronoun they was lost during the early transmission of the text, perhaps as Oliver Cowdery copied from 𝓞 into 𝓟 or as he took down Joseph Smith’s dictation for 𝓞. The omitted subject was probably the short pronoun they rather than a full noun phrase such as “these words” (which is found later in verse 9: “and he shall deliver these words unto another”).
David Calabro (personal communication) suggests that another possible subject pronoun that could have been accidentally lost is it:
Here the it could refer to either the book or the words as a collective whole. In support of this alternative, there is one clear example where the scribe (in this case, Oliver Cowdery) omitted the pronoun it, at least initially, as he copied from 𝓞 into 𝓟:
We should note, however, that this example involves the loss of the it in object position rather than in subject position. One possible example involving the loss of a subject it can be found later on in the text when scribe 2 of 𝓟 was copying the text from 𝓞 into 𝓟 (here the 1830 edition is also a firsthand copy of 𝓞):
This example, however, is complicated in that there appears to have also been an accidental omission of the modal verb must in the original manuscript (which is not extant here). See 3 Nephi 28:37 for discussion of the emended reading “or else it must needs be”.
In general, however, there is not an abundance of evidence that the Book of Mormon scribes tended to drop the pronoun it. (For another example of the possible loss of an object it, see Jacob 5:24.)
On the other hand, there are numerous examples of the subject pronoun they being accidentally omitted in the manuscripts:
Usage elsewhere also favors the occurrence of the pronoun they, not it, in the context of “the words”. Besides the they in 2 Nephi 27:6, there are in this same book of 2 Nephi four occurrences of they that refer to someone’s words:
Thus the internal evidence as well as evidence from scribal errors shows that the later insertion of they in 𝓟 for 2 Nephi 27:6 is most probably the correct reading.
Summary: Maintain in 2 Nephi 27:6 the corrected text in 𝓟 (“and they shall be the words of them which have slumbered”); most probably, the they was accidentally lost in the early transmission of the text.