Not uncommon - a new car can sit in a impound / import lot for some time - then on a train - then on a truck - then sit at the dealer. Put a battery through some cold temps and no fresh charge and it will get soft - kill it leaving a light on during dealer prep etc and your buyer might be calling you very soon with a non start due to a dead battery. It takes a pretty decent drive to get a batter charged all the way back up. Also if the battery was killed and was in bad shape before having a light left on - it may not actually accept a full charge and need to be replaced.Apparently when they want to go fill up the tank yesterday it had a dead battery. Someone had left the dome light on and drained the battery completely. The technician had to jump the car, fill it up with gas, and drove back to the lot. When we got there the car was sitting in the lot running. Today the technician replaced the battery and told me they check engine light was due to the crank angle sensor. He call me back at lunch and said that car is "perfect". Now my wife and I both have to drive 30 miles back to the dealership pick it up and drive back home that takes at least an hour and 15 minutes. Can you say free oil change?
So if they didn't replace the battery for you - keep a close eye on it for a bit make sure the battery seems healthy and is giving you a strong start etc.