Ashley from the American Antiquarian Society responded:
The broadside that you reference has an estimated date of 1776-1805, as the Bible and Heart in Boston was the sign of T & J Fleet from 1776-1797 and John & Thomas Fleet from 1797-1805. This information is taken from the AAS catalog record at http://catalog.mwa.org/vwebv/holdingsInfo?bibId=509056. The imprint reads: "Sold at the Bible and Heart in Cornhill, Boston."