Here's the thing... say you're at an interview and you get this question:
"Hmm.. I see you took a Calc 1 class the summer before you graduated... but you had already taken Calc 2, why was this?"
At that point, just about any answer you give wouldn't be good enough, and it'd be a safe bet that you just ruined your chances for admissions to that school.
Just to raise your GPA a tiny bit, this is a HUGE risk that isn't worth it. If you want to take a class to raise your GPA, take something else. I took "Global Change Biology" which was a total cakewalk class during my senior year because I needed more units - if you want to look less shady, and be able to give even a semi-legit answer at an interview about it, you should take something that could possibly interest you, or just some other random science.