Well I had almost the exact same thing happen to me, only I was the one hit. I thought it through as I waited for the police to arrive. I pocket carry a LCP so no way it would become "open" but that's legal here too. I just figured since I was going to be in and out of the car alot I would simply inform him. So when the other driver went back to his car, I showed the officer my license and carry permit and stated, I have this (permit), and all that goes with it in the car's center console. Not even looking up from what he was doing, he replied okay and walked away. So I guess he didn't care in the least. It's a personal choice and depending on the circumstances I may choose differently the next time.
Ruger LCP, XDM 9mm Compact, HK45c