Non-fiction: There once was a famous gunsmith in St. Louis -- Samuel Hawken (1794-1884). His 'Rocky Mountain Rifle' became famous in the Wild West, and any 'Westman' worth his salt, owned a 'Hawken Rifle'.
Fiction: Karl May, aka, Charley the greenhorn, later Old Shatterhand, started his Wild West adventures in St. Louis, where he met an old gunsmith called Mr Henry. They became good friends. When it was time to head off into the unknown, Charley, his host family in St. Louis (German immigrants), Mr Henry, and a 'Westman' by the name of Sam Hawkens, who owned a battered, but reliable old rifle he called 'Liddy', were sitting at the same 'farewell dinner' table. The German immigrant family were the supporting cast of the main event: the splitting of real Samuel Hawken and his Rocky Mountain Rifle into three parts.
Where fact and fiction meld: Mr Henry the fictional gunsmith, Sam Hawkens the 'Westman', and Samuel Hawken the real gunsmith had one thing in common - they were one and the same. At that dinner table, Samuel Hawken morphed into Mr Henry, and his name was carried west by the 'Westman' called Sam Hawkens, whose gun, 'Liddy', was undoubtedly (meant to be) a Hawken Rifle. Fictional Mr Henry designed and built the fictional 'Henrystutzen' -- in the fictional Wild West of Karl May's making, that 'Henrystutzen' became the most famous gun in the West, a fame borrowed from the real Henry Rifle; the reputation of reliability was borrowed from the real Hawken rifles.