William Arms Fisher, the African-American composer who studied with Anton Dvorak, published books of scores for Oliver Ditson Company, which were influential in versions sung in choir and concert.
W. A. Fisher, "Seventy Negro Spirituals," 1926, published a full score for "Were You There (The Crucified)," pp. 195-197. Oh! is four note, mezza voce for voice (col voce for piano accomp.). Oliver Ditson Co.

The Hampton Institute, as transcribed by R. N. Dett, shows the Oh! as two note, rising. (Ref. in previous post)

Johnson and Johnson, "The Books of American Negro Spirituals," II, pp. 136-137, has the Oh! as four note.