You should not leave the scene of an accident, without leaving your contact information with the owner of the property you damaged. Now you left the scene of an accident, without leaving your contact information with the owner of the pedestrian sign, you action already constitutes hit-and-run.
Now it's too late to go back and correct your action. It's like returning the things you stole, that might mitigate your punishment, but it does not mean you are innocent.
Luckily for you, I don't think the damage is such that warrants the police or the plaza owner to pursuit legal action against you.
Next time you should stop your car, take a picture, and leave your contact information on the damaged sign. That satisfies your legal duty.
