A Barlow pocketknife would not be out of place in an 1830s rig. The Barlow brothers of Sheffield manufactured Barlow knives, but many other manufacturers made knock-offs, and eventually Barlow became a generic name for that style knife.
Carl Russell, who wrote "Firearms, Traps, & Tools of the Mountain Men" (1967, Alfred Knopf), states that pocketknives, and Barlows in particular, were quite common on the western frontier throughout the late 18th and early 19th centuries. (The book is out of print, but worth looking for on the used book market. )
One short excerpt:
"A tremendous number of cheap Barlows were manufactured in the Stannington district, near Sheffield, by several firms, so many came from there that the name "Stannington Barlow" was coined. A Barlow knife is a jackknife, of course, that dates back to the seventeenth century. The distinguishing feature is the extra long bolster. Legend has it that the brothers Barlow devised this feature in order to give strength to the cheapest jackknife they could make. Other manufacturers adopted the long bolster, and their knives also became known as Barlows. The type is still on the market and is still named Barlow."
Sketches of pocket knives known to have been used on the western frontier in the late 18th and early 19th centuries:
