Hey John:
In your trade, did you call the local police department and have the serial numbers of that S&W 4506? You don't know, it may be stolen.
And if YOU get caught with a stolen gun because some officer runs it through, YOU are in trouble. At the very least, you lose the gun.
I never buy or trade any used gun without running its make, model, caliber and serial number through the police.
The National Crime Information Center (NCIC) is a computerized, national databank containing the serial numbers of stolen guns going back decades. These entries are never removed, except when the gun is recovered or when the agency that entered it requests its removal (a rare event).
When I was a reporter in Idaho I did a piece on a Mauser rifle found at a hock shop (which are required by law to submit the serial numbers of all guns they take in trade). The rifle had been stolen from a Texas home some 15 years before! NCIC found it and it was returned to the Texan who probably thought it lost forever.
My brother had a .38 revolver stolen from his home in Memphis, Tenn. It turned up 9 months later in a hock shop in Shreveport, La.
We, as gun owners, have a responsibility to police our own ranks.
Anyway, didn't mean to go on a rant but I wanted to emphasize something that should become second-nature to every gun enthusiast. Unless you buy it new in the box from a dealer with an FFL, run it through NCIC BEFORE money changes hands.
Once you buy it, the police will not reimburse you. And you'll likely have a heck of a time getting the money back from whoever sold it to you.