If you file a police report and claim the owner of that car will get a call from his insurance agent saying that there is a report that they were involved in an accident, notified and left the scene. Mention that you have evidence of the imprint left by the plate. Do not get into details about the holes unless specifically asked. But do mention that on the accident report. You should always take a pic but no worries if you did not. If push comes to shove the holes matching will be enough to give you the advantage. They adjuster will easily approve a repair or replacement of your bumper and the other guy will get surcharged and hopefully learn to be a better parker. I had a neighbor that did that to everyone and when I saw him do it and called him out he said it was an accident and happens to everyone and I pointed out that there were multiple pant scuffs on his front and back bumpers so it wasn't a one time incident. The pictures of my unscuffed bumper with the two holes that matched the license plate of his bumper with all the scuffs was plenty enough to win. He had the nerve to say that the holes were caused by me bumping into him :) Good luck!