See Roster of South Carolina Patriots in the American Revolution, p. 14, Genealogical Publishing Co. 1994, Baltimore , MD
There is a listing:
Allen, John Peter He enlisted in the Second Regiment on February 1779. In addition, he was under Capt. Peter Gray and Co. Marion and was made a corporal on 1 February 1779. He was a private on 1 July 1779. Saffell, p. 292; N.A. 853.
There was also another John Allen listed on the same page, (no middle initial or name), but the listing above matches the Daughters of the American Revoltion records of John Allen who married Elizabeth Lindsey.
DAR verified this for me in April 2007, (Reference code is RZJYXABK).
I also have this in my records:
Texas Society - Daughters of the American Revolution
Members: Stella Allen Buchanan....no. 344891
Allen John (Peter), born 1743 in Surry County, South Carolina; died June 8, 1822 near Woodruff, South Carolina. Married.Service:Private and corporal, 2nd South Carolina Regiment under Lt. Colonel Francis Marion.
Children: 1. William L. 2. James married Mary Woodruff 3. Mary (Woodruff) 4. Susannah Pace 5. John 6. Caleb, born December 15, 1785, married Elizabeth Woodruff 7. Micajah 8. Matthew, born Dec. 15, 1792, married Rebecca Drummond 9. Lucretia 10.Elizabeth