Tyrell was in her case much worse because she did not know she was a replicant and her memories were only that of the Tyrell niece "to make her more human". She also, after having learned that she is not human, shows a photo of her as a little girl and her mother to Deckad to certify her past. Deckard himself learns that the photos are of certain importance to them when he, not really conscious of what the real nature of replicants might be, said: "Maybe they were like Rachel, they needed memories".
The mother on the Rachel's photo might be another important clue for a notion of history in the film. We encounter the "mother" several times, once right in the beginning when Leon being questioned by the Tyrell's people to identify whether he is a replicant or not, and when asked by the inquirer about his mother, stands up and shoots him. ("My mother? I'll tell you about my mother…") The second time when the mother becomes important is the already mentioned Rachel's fake photo where the mother figure is to affirm Rachel's "identity over time". Consecutively, the photographs in Blade Runner acquired the status of being the document of "what-has-been", they "represent the trace of an origin and thus a personal identity, the proof of having existed and therefore of having the right to exist".
To conclude, the Scott's futuristic vision Blade Runner is a film in many ways very much expressive, mirroring the "so far" experience of the humanity and bringing many striking and powerful suggestions of which humanity is, in my view, most touching. Even if the sci-fi genre was not particularly appealing to me, Blade Runner was a very bright and extraordinary exception.