It may violate more than NCIC policy. However, there are other databases that LEO may be able to run serial numbers through. I know that our local LE uses something called "Leads Online" to check for stolen goods.
A gunfight is not the time to learn new skills.
If you ever have a real need for more than a couple of magazines, your problem is not a shortage of magazines. It's a shortage of people on your side of the argument. -- Art Eatman