Guns drawn and slapping handcuffs on them was "appropriate"? I don't think so.
Well, think about it.
The police are looking at a vehicle that is behaving suspiciously, and on a license plate check, it comes up as stolen. What do you expect them to do?
Now, the police have to realize there is always a possibility that the database is wrong, and the vehicle was not stolen. But if it is on the list of stolen vehicles, it probably is stolen. You have to figure that the list is right more often than not, right?
So, if the vehicle was stolen, would there have been anything wrong with following the procedure for a high risk traffic stop? Job #1 on a high risk traffic stop is to control the situation and eliminate the possiblity that the occupants of the vehicle, who you figure at a minimum are probably car thieves, can resist. So you stop the car and gunpoint, remove the occupants, secure them (with handcuffs), and then check the registration.