I agree with @ucbalumnus @PrimeMeridian and @T26E4
When I was going through the admissions process, I went to an Exploring College Options event, which had reps from Harvard, Stanford, Penn, Duke, and Georgetown, among others. During the Q&A, someone asked, “What do you think of applicants who self-study for additional AP’s over and above the AP classes they take?” One rep responded, “Please don’t do that. We’re not impressed by that.” The other reps all nodded.