All in all, I'd take their word on it, and let it ride.  If it was like the officer said, then they get by with one.  Not THAT big a deal overall.  If it happens again, obviously the officer would be more inclined to at least take a picture of it.
If I had an issue with it, I would have paid for it, took pictures after having it in my possession at the pizza place, and then go from there.