The previous verse refers to Mormon making his record (“I have made my record of these things according to the record of Nephi”), so it is possible that here in 3 Nephi 5:11 the original text read the record. The 1830 edition has the, and Oliver Cowdery initially wrote the in the printer’s manuscript. Later, with distinctly heavier ink flow, he corrected the the to this by overwriting the e with is. The 1908 RLDS edition followed the corrected reading in 𝓟, but the LDS text has continued with the 1830 reading.
One possibility is that 𝓞 had the record but that this was an error for this record. In that case, the change from an original this to the would have occurred during the dictation of the text. As already noted, the preceding verse with its phrase “according to the record of Nephi” could have prompted the change in verse 11 to “I do make the record”. Moreover, there is considerable evidence that Oliver Cowdery could have made a mistake like this in 𝓞 (namely, writing down the instead of this). Under Helaman 14:20, I list seven clear cases where Oliver mistakenly wrote the instead of this in the manuscripts. In almost all cases, the error was corrected; but in one case (in 2 Nephi 1:8), Oliver permanently replaced the this with the as he copied the text from 𝓞 into 𝓟.
Of course, these errors on Oliver Cowdery’s part show that he could have changed an original this in 𝓞 to the in 𝓟. Similarly, there is evidence that the 1830 typesetter could have replaced an original this with the; there is one clear example, in Mosiah 1:10, where he made such an error. (For an example where he seems to have intentionally changed a this to the, see under 2 Nephi 10:23; also see the discussion regarding this versus the under 3 Nephi 5:12.) So there is some possibility that both the 1830 typesetter and Oliver could have misread an original this in 𝓞 as the. Again one could argue that the preceding phrase in verse 10, “according to the record of Nephi”, led to the error in verse 11. Under this interpretation of the variation, Oliver later caught his error when he proofed 𝓟 against 𝓞 (thus explaining the heavier ink flow for the correction in 𝓟), but the corresponding error in the 1830 text was never caught during proofing. Yet the odds of both Oliver and the 1830 typesetter making the same mistake seems somewhat unlikely, especially since comparatively speaking there is only minor evidence for the 1830 typesetter accidentally changing this to the.
Another possibility is that the change of the to this by Oliver Cowdery in 𝓟 was the result of conscious editing on his part. The correction in 𝓟, with its distinctly heavier ink flow, could be interpreted this way. Moreover, when we consider other occurrences of “make this record” or “make the record”, we note that the record is consistently postmodified by a restrictive relative clause:
On the other hand, there is no postmodification for this record:
These results support the reading this record in 3 Nephi 5:11, either as the reading in 𝓞 or as the reading of the original text. On the other hand, one could argue that Oliver Cowdery expected this record, with the result that he later decided on his own to emend the record to this record in 𝓟.
Nonetheless, this regularity applies only to the specific phrase “to make this/the record”. More generally, the singular the record is postmodified most of the time:
followed by an of prepositional phrase 28 times
followed by a relative clause 8 times
followed by thereof 1 time
But in at least six cases in the original text, there is no postmodification for the record:
Thus the record will work here in 3 Nephi 5:11 since there is an earlier reference to Mormon’s record in verse 10 (as my record ). My suspicion is that the corrected this record in 𝓟 was the result of conscious editing on Oliver Cowdery’s part. Thus the critical text will retain the less expected but possible reading, the record, in 3 Nephi 5:11.
Summary: Follow in 3 Nephi 5:11 the 1830 reading, the record (which is also what Oliver Cowdery originally wrote in 𝓟); 𝓞 most likely read the record, but later Oliver emended 𝓟 to read this record, which is what he expected here since the record was not postmodified; specific usage elsewhere in the text supports this record, but more general usage shows that the record is possible.