Goes to did he buy if from a stocking S&W dealer, or was it picked up in the aftermarket? A previous owner could have simply sent it in for ceracoating.
A check of the serial number and it's potential date of manufacture wouldn't hurt, as it may reveal with a bit of sleuthing if it was part of a contract run for a particular agency. That is doubtful considering the gun would be in competing for contract with a polymer striker fired which would have a price advantage.