Question about M&P serial number prefix

[oldpink]

I have a question about a used gun that a guy I know just bought for a great price.
It's a full size Smith & Wesson M&P in .40 caliber with some wear, around the rear sight especially, and the serial number has the prefix "CPD," which to me sounds like a police trade-in, but I don't know if the specific department (Cincinatti? Chicago? ???) could be found somewhere.
Does anyone have any ideas about this one?

 

[in625shooter]

It very well could be a Police trade in but I believe Cincinatti went with the M&P 9 from their 5900 series.

I'd call S&W and ask.

 

[oldpink]

Yep, I'll suggest that the guy do that.