"A man; specif., the exact kind of man needed for a particular purpose. 1936: "Well, I'm your huckleberry, Mr. Haney." Tully, "Bruiser," 37. Since 1880, archaic.
The "Historical Dictionary of American Slang" which is a multivolume work, has about a third of a column of citations documenting this meaning all through the latter 19th century.
So "I'm your huckleberry" means "I'm just the man you're looking for!"
- "well Ramone got that huckleberry who pays to suck his dick - u can use him AND get some readies."