Help Me Please

My community college don’t give out +/-. I got a C, even though I should have gotten a C+. Should I do an addendum and tell the school I’m applying to that I had a 79.5%. Would they even believe me? Maybe I can print out the grade sheet because my professor posted all grades online, and I printed it out at the end of the semester. But I don’t know if they would believe me or think that it is a fake.