Sorry, Q...I only assumed you were kidding because it was in a previous post. But that WAS a long time ago.
So, to recap: Robert W. Gordon collected songs with the refrain "Come by here" in its various pronunciations (including "come by yuh") four times on his Georgia trips in 1926-1928. Lomax recorded a version in 1936. These were all prior to Frey's composition.
The version in the Society for the Preservation of Spirituals book is probably not from one of the Gordon cylinders. The exact date and location of collection are not mentioned, but given the activities of the group's members, it must have been noted in South Carolina between 1922 and 1931.
Some versions of the song were certainly in the Gullah dialect. Whether it originated that way is not known.
So GUEST is mostly right. The one thing that cannot be proven is that the song dates back to slavery times. There is no evidence of that...although such evidence is scarce for any spirituals. So it is at least somewhat likely that the song does date back that far.