I have no inkling if such a thing might have been done in the mid- late 19th century
Being computer illiterate as I am, I do not have the where withal to scan and download the illustrations I will refer to, but please feel free, if you have access to the material. In Clifton Edom's Missouri Sketch Book, Kelly Press, 1983 on page 7, is an illustration by an artist by the name of Dallas, for Harpers Weekly, showing Border Ruffians coming from Missouri to Kansas, some on horseback, some on foot. A man on the right side of the illustration is on foot and appears to have a "hasty sling" with buckle. Perhaps former militia, but in 1851, the majority "military" action going on in the midwest of note was covert, not organized. Another illustration I wish I knew how to post is found in The Golden Book of The Civil War from American Heritage. On page 23 is an illustration, again portraying Border Ruffians of the 1850s, source: Mabel Brady Garvan Collection, Yale University Art Gallery. Again, some of the bushwhackers are mounted, some on foot, rough clothing, buckskin? fringe, powder horns, no militia evident, and the man in the forefront, mounted, is carrying an American Plains Rifle over his shoulder, utlilizing what appears to be a hasty sling. Now, with my research experience, I would not necessarily rely on only 2 illustrations for a point, but a degree of a point is to be made. These are works by artists of the day, though they may have reason to highlight specific nuances(sp) due to their political stance, they would not have reason to misinterpret something as incidental as a hasty sling. Granted, these men are not traipsing through the back woods of Tennessee, they're on the Kansas prairie. They do not have anything in their hands. The border Ruffians traveled in groups, coming from various and sundry points in Mo headed West. If one or more in a given group being illustrated happen-stance as it were by a reporter of the day, and were utilizing a hasty sling, would it not be too much of a stretch to imply that other ruffians, traveling in their own groups, were using hasty slings? And as such, not as rare as we would assume.