OK, here's Hamill's source. It comes up in the controversy over the site of composition--to settle which was Hamill's original research goal: "Hamill's evidence against Georgia's claim is a playbill found in Harvard University's Houghton Library, which lists a performance Boston's [sic] at Ordway Hall on September 15, 1857 of "One Horse Open Sleigh"--the original title of "Jingle Bells."

This is on the website of WCVB, an ABC affiliate:

www.wcvb.com/article/debunking-the-local-myth-about-where-jingle-bells-was-written/8514578