Yes is the answer to your question, at least it was the first record with any commercial success...the sample used was Chic - Good Times which was a hit in June 79 and Rappers Delight was a hit in December 79.
Rapper's Delight backing was not from a sample. The Sugarhill records studio band re-recorded Chic's song as there was an issue with copyright. True: the Sugarhill Gang probably wrote the song with 'Good Times' being played as backing, but when it came time to record it, the backing was not Chic, but a studio band. The bass player you hear is Doug Wimbish and drummer, Keith
LeBlanc.