From the American Almanac for September 1840:
A numerous assemblage of the political party styled Whigs, from every county in Massachusetts, and most of the States in the Union, called the Bunker Hill Convention, meets at Boston, for the purpose of promoting the election of General William Henry Harrison to the presidency of the United States. A procession was formed on the Boston common, and proceeded, eight abreast, by a circuitous route more than four miles in length, to Bunker Hill, the van of the procession reaching Bunker Hill before the rear had left the common. The number in the procession was computed at about 20,000, about 1,500 being on horseback. A declaration of principles was read at Bunker Hill by Daniel Webster, the President of the Convention.
This ribbon was originally issued for the Harrison Jubilee of July 4, then repurposed for the Bunker Hill Convention. We can't recall seeing it before.