Jenson gives date for Able's ordination as an Elder and a Seventy.
Andrew Jenson, Latter-day Saint Biographical Encyclopedia : A Compilation of Biographical Sketches of Prominent Men and Women in The Church of Jesus Christ of Latter-day Saints, 4 vols. (Salt Lake City, UT: Western Epics, 1971), 3:577
ABEL, Elijah, the only colored man who is known to have been ordained to the Priesthood, was born July 25, 1810, in Maryland. Becoming a convert to "Mormonism" he was baptized in September, 1832, by Ezekiel Roberts, and, as appears from certificates, he was ordained an Elder March 3, 1838, and a Seventy April 4, 1841, an exception having been made in his case with regard to the general rule of the Church in relation to colored people.