Not necessarily because you don't know a school's intentions. At this point, a school may still be determining their regular class seats OR may be compiling their alternate list. You would not know unless you ask the particular school to which you are interviewing.
However, a couple of key things to remember about the interview. One thing that is for sure is that you are vying for something, and because of this, you should put your best foot forward. Also, it is common for interviewers to know nothing about you before your interview, otherwise it creates bias. Interviews tend to center around your value system. I wouldn't try to talk to much about your academic record because a school already has it on paper, unless you can tell a story about yourself through one of your classes (the grade is not of importance but rather your perserverance).
The interview should be viewed as another element in the selection process. I wouldn't say that it supplants everything else (if that was the case a school would not ask for your grades/PCAT scores and there would be no PharmCAS) but it could make your application appear more favorable in the end. It really depends on how much emphasis a particular school places on the interview.
Remember something very important, the interview is the last chance you have to "sell yourself" to a school. Make the most of your opportunity and good luck!
