[medalguy]

To add to Jim K's post: BATF switched their filing system from drawers full of file folders to electronic a good many years ago. During that switch a few documents didn't make the jump, so if a LEO inquires about a specific firearm by serial number, it may return as no information on file, particularly if it was transferred many years ago or is an amnesty gun. That could present a problem if you are involved in a discussion with a LEO. They may have the paperwork, it just does not come up when they do an electronic search. It's always best to have your copy of the registration paperwork with you.