According to Dichter and Shapiro, "Early American Sheet Music," 1941, p. 141 (quoted in Randolph, Ozark Folksongs, vol. 3, p. 332) "Buffalo Gals" was published by William Hall and Son, NY, 1848. Richr (early post) quotes from Brown about its similarity to a German tune and to "Lubly Fan...." which was published in 1844.
It was certainly widespread by the mid-19th century, in many guises, and tying down its origins will be difficult.
Looking forward to the verses Rich-Joy has.

The 1844 minstrel tune, "Lubly Fan Will You Cum Out To Night?," by Cool White (Hodges) in the DT and in Joe Offer's post above, lacks one verse from the original sheet music (5, just before the oyster plant verse):

I lub to taste dem lubly lips,
Lubly lips,
Lubly lips,
Oh den I sure would lose my wits,
An' drop down on de floor.
Cho.:
Den lubly Fan will you cum out to night, etc.

Sheet music reproduced in: Three Centuries of American Music, vol. 1, American Solo Songs Through 1865, Ed. Nicholas Tawa, G. K. Hall & Co, 1989, pp. 107-108.