Only witness to Rachel's death says has no memory of any conversation...
...and from what I can tell, her "last words" are just urban legend. He only recalled hearing her crying.
I'm a born-again Christian and I'd be thrilled to hear that her last moments were filled with such impactful words and meaning---but I prefer reality to fantasy. The young man who was next to her was hit by many bullets and has no memory of anyone questioning Rachel. This sounds like a hearsay story which got out of control.
She sounds like a wonderful person who deserves to have her story told. What was special about her happened in her daily life BEFORE her death, not her last minutes of life. However, making money by making movies depends on an uplifting and emotive story, not on necessarily telling the truth.
The Cassie Bernall story was similarly turned into a last-seconds-before-death scene fantasy. Neither the Scott nor Bernall mythology fits what appears in the actual official record gleaned from a careful questioning of all witnesses.