I might be wrong, but doesn’t the vagina show specific signs of rape vs consensual sex?
Not necessarily - consensual sex can be very rough (there are people who like it that way) and rape sometimes isn’t violent in that way - somebody forced to submit at gunpoint may not struggle for example. Injury is certainly something that is looked at as possible evidence, but doesn’t necessarily mean that much, nor does the lack of it.
And in this case, the allegation was that the rape had occurred years before.