Yes, that Rosa Parks. As this article from 1992 about her autobiography entitled Rosa Parks, My Story, states that her "Scotch-Irish great-grandfather was imported to Charleston, S.C., as an indentured servant". Similar comments are here in an article in The Washington Post in 1995.
He was James Percival (1832–1920), an indentured servant on the Wright estate of the town of Pine Level, Montgomery County, Alabama. He married African-American Mary Jane Nobels, who was a midwife and slave on the same estate. They had nine children.
Like everyone, Rosa Parks would have had 8 great-grandparents, of which James Percival was only one. Yet James Webb saw fit to mention her in his book Born Fighting, because, like Barack Obama, she apparently mentioned her Scotch-Irish ancestry in her own writings. That is surely significant. If anybody out there has the original source I would be very interested.
NB: There can however be an unhelpful 'elasticity' with the usage of the term Scotch-Irish, so it's always important to verify the sources. Sometimes it has been used too broadly, being used to mean someone whose ancestry was from either Scotland or Ireland, so not necessarily Ulster at all.