This excerpt recognizes that Lafferty/Abney mention gold in Texas:
Of other publications of older date, such as D. Woodman’s ”Guide to Texas Emigrants;” David R. Edwards’s “The Emigrant’s, Farmer’s, and Politician’s Guide,” provided with maps, the notes about the country west of the Pecos, even west of the Colorado River, are perfectly worthless, the maps not much better than fictions.
The life and adventures of L D. Lafferty, by A. H. Abney, claiming to be truth, mentions the presence of gold in Texas. Other publications, though some of them are quite interesting, do not extend their narratives west of the Staked Plains, and state more the adventures of the parties (surveyors and
hunters) than the approximately correct (geographical, etc.) character of the country.
Source: Geological Survey of Texas; Report of the State Geologist 1890. GoogleBooks