The performers of the 1963 girl group classic “My Boyfriend’s Back” might well be tempted to pen new lyrics after a unanimous Manhattan court ruling yesterday: “My lawsuit’s back, and you’re gonna be in trouble…” Forty-seven years since “My Boyfriend’s Back” hit number one on the charts, the Appellate Division, First Department, restored two of six claims accusing F.G.G. Productions, which produced the song, of failing to honor its contract to pay royalties.

The lawsuit was brought by Phyllis Sirico, one of two sisters who sang backup for the Angels, and Peggy Davison, the group’s lead singer for “My Boyfriend’s Back,” which sold 1 million copies. Ms. Davison joined the Angels in 1962, and was not a party to the 1960 agreement with F.G.G., whose three partners wrote the song. F.G.G. acknowledged a contract but contended that Ms. Sirico had forfeited any rights to royalties under a provision that barred the group from recording for any label other than those F.G.G. had licensed.