I've lost track of all of them, but yeah I think you're right--there was something about it not matching, but I wasn't clear how a 'witness' would know that.
It's so difficult to remember every detail. I remember that initially they discounted the tag number, I thought because it didn't match up with the vehicle description or because the owner was cleared. Then I thought something came out about it being rented. I'm probably confused on that point.
When the witness told the police about car/p/u and tag#- it came out from police that the tag the witness claimed didn't match the car.
I'm not sure if it was the white pick up though. Hopefully, some poster will correct this or add to it.