I found this link, which answers my questions, and I thought I'd pass it on:
http://www.guncite.com/gun_control_registration.html
If I'm reading it correctly, law enforcement would basically have to know beforehand the FFL from whom you purchased your handgun and physically go there to check his log to see what you'd purchased.
But what happens to all those logbooks at the ATF when the FFL retires from the firearms business? My dealer is closing his business down and, I presume, retiring from the firearms business. When he surrenders his log, is there some guy at ATF who goes through it and says, "Hey, this Joe Smith guy sure has bought a lot of guns. Hmmm....maybe better check him out?"
I have to rant a little here. The business, The Trophy Room in, Alexandria VA,
is closing because the city's ridiculous zoning laws won't let them expand because it would mean altering a "historic" shed in the alley.
So, after six years, a successful business (and guns are only a small part of the quiality sporting goods they sell) is going to shutter it's doors. To be replaced, no doubt, by some tacky t-shirt shop for all the tourons.