The guy told me it was a Performance Center Gun with a Black T finish. Looks and feels like a Black T type finish to me, and the action is flawless. If it wasn't offered by the Performance Center, I think he must have sent it to the Performance Center for after-market custom work. He wasn't a lying type of person. Ex Marine, stand up sort of fellow.
So, maybe I should have asked what model it is, my assumption is that it was a M586. If it is, the PC never made one, to my knowledge, without a power port compensator. I could be very wrong, but if that is a M586 with a serial prefix BDT/BDY range, it's probably one of the 1989 models.
Can you provide more info? Model number, serial prefix, etc. It's a nice looking gun, but again if it's a M686 that's been Black T'd then I can't tell you anything about it. I'm not aware of any PC M686's with 4" barrel that didn't have a comp of some sort except some of the more recent slender slab models, but I don't think those are PC either.
Here is one of the M586 Special Production guns from 1989, looks a lot like yours....
Neat gun.....
Updated - I see you mention M586, does it have a dash number after the Model number? The Special run guns were no dash from my recollection and notes. Also, if the serial number prefix is as noted above, it very well might be the Special production gun mentioned. If I'm not mistaken, these may have been shown in the 1989 S&W annual product catalog, there were a lot of special guns made that year, including a M686 that was blackened.....
One last comment, if you call the factory (800-331-0852) and ask for Customer Service (select #7), they can tell you the product code for your revolver if you provide the serial number. With the product code, we can match with the SCSW list.