Isaiah 7:23 (King James Bible) and it shall come to pass in that day that every place shall be where there were a thousand vines at a thousand silverlings
The original reading of the printer’s manuscript (“that a thousand silverlings”) seems impossible. The 1830 compositor corrected the printer’s manuscript to agree with the King James text. The original manuscript is not extant here, but a very likely possibility is that Oliver Cowdery (the presumed scribe here for 𝓞) misheard Joseph Smith’s dictation of “vines at” /vainz æt/ as /vainz dæt/. The extra /d/ could have been introduced because of its phonetic similarity to the /z/ at the end of vines (both /d/ and /z/ are voiced fricatives in the dental area of the mouth). For other examples of phonetic misinterpretation in 𝓞, especially across word boundaries, see the discussion under 2 Nephi 16:9.
Summary: Follow the 1830 typesetter’s emendation that replaced that with at; this change agrees with the King James Bible and removes an impossible reading that was probably the result of the scribe mishearing Joseph Smith’s dictation of vines at.