Canonically, yes. Specifically, she's the biological daughter of the Scott and Jean of Earth-811.
In Claremont's headcanon, no. She's the daughter of Jean-811 and the Phoenix Force and unique in the multiverse. There are other Rachel Summers-es, but none of them are alternate versions of her.
In Jogan shippers' headcanon, no. She's the daughter of Jean-811 and Logan-811, the by-product of an extramarital affair so intense, erotic, and sexually satisfying that it gloriously cuckolded every version of Scott Summers across the multiverse for forever and all time.