Here is what it means.
“In the 1800s, the phrase “I’m your huckleberry” was used to mean “I’m the one you want,” or “I’m the right one for the job,” or “I’m the right match.” Essentially, it meant that one was up to the task at hand.
In Doc Holliday’s case, it meant that he was up to dueling with Johnny Ringo.”
“look through newspaper archives of the time and you’ll find all sorts of examples of the phrase “your huckleberry,” and they all have the same context: I’m your guy. Or gal. Or sweet potato. Or acre lot near the railroad station. Or pie. You get the idea.”
Thank you, that’s awesome research. Much appreciated.