Personally I would have done the same if faced with identical circumstances. If they treat me with respect I will return the favor. In the end you are doing your small part to chase down leads to try and solve a crime. The upside would be presenting an image of responsible private gun owners to 6 ATF agents to let them know that not everyone that owns a gun is a nut.
The only thing that bothers me about the account is the probabillity that the federal government does keep track of every transfered firearm indefinately which would remove the need for registration before a nationwide confiscation could take place.
