Medical schools will see all of your scores, even if they say they will not.
Some schools will directly say "We average your MCAT score/use lowest/use highest/use most recent/etc."
Interviewers in open-file interviews will have access to all your scores, and it will be analyzed in their own way. Some interviewers intrinsically average. Others understand people make mistakes and will ignore that 501 and judge you as a 513 on your re-take.
My experience:
First MCAT was = to 505 (it was on the 45 pt. scale).
3rd mcat was marginally more competitive, enough to land me several interview invites and a few acceptances, MD and MD/PhD. Note, my application outside my MCAT was rather superb; many publications, volunteer hours clinical and non-clinical, variety in leadership, solid letters of recommendation.