That’s a legend spread by Hardin in his 1896 autobiography. The event supposedly happened in Abilene, KS in 1871.
Hardin biographers Chuck Parsons and Norman Wayne Brown say it’s a myth. Hardin was the only source for the story, and he only made it after Hickok was dead. Plus, the newly elected marshal knew about Wes’ reputation—he would have been especially careful around the youngster.
The authors say Hardin lied—which he did pretty frequently.