Sure. The government database presumably covers "all the guns". The private one includes some subset of guns, for example, all those whose owners want to subscr

Sure. The government database presumably covers "all the guns". The private one includes some subset of guns, for example, all those whose owners want to subscribe to a certain gun manufacturer's newsletter, or all guns whose owners opted into a warranty program despite knowing it would get their names in a database. The fact that this particular database included data collected under false pretenses shouldn't preclude anyone from making a mailing list of gun owners.