Durant MSS

A while ago, while back my truck out of a drive way, I backed into another truck that belonged to a friend of mine (we both had the same model). My bumper scraped the side of his car, near the area of the gas tank. There were white scratch marks, but since my truck was red and his was green, he thought there would be a red smear or at the very least there wouldn't be white marks since the bumper has no color. Basically, he thinks that someone else hit his car and not me because of the white smear (the car had to be white). Is there anyway I can prove that it was my car and nobody else's that backed into his? We both were driving Ford Rangers, I don't remember the year or model though.