All through the 5 years i've had my P3AT it has been a lot of trouble. After trying to fluff and buff, clean it etc i sent it in. When i finally got it back, the parkerized slide was replaced with a blued slide. I didn't know that this was less valuable until a long time later (actually a few days ago). It soon developed a new problem and off it went again about a week ago.  
 
Parkerized steel is much more protected than blued, so I kind of feel ripped off. If i'd have known this, I would have included a note in when i sent my pistol about this lousy replacement they did.

I'd just call. As said most likely an oversite. They can tell by S# what it was built as.
 So ya got the slide back blued and the barrel back parked, I'd think that would have been noticeable

Parkerized units come with parked barrels , blued come with raw steel (gray bare metal) it should have been very obvious to the factory it was a parked slide if the barrel was parked (black)  
I am sure they will make it right for ya good luck

If you had the gun 5 years, it has to be a 1st. Gen gun.
 
As such, it is very possible they don't still have any parkerized replacement slides left, and put on what they had available.
 
The new 2nd. Gen slide with the external extractor spring will not fit a 1st. Gen gun.
 
rc

If it was a 1st gen gun, I'm surprised they had ANY slides and barrels for it.  While most all the little internal parts are the same, my understanding is that they no longer make the major parts, slides, barrels, etc, for the 1st gen guns.  Typically, if a 1st gen guns needs those parts they must replace it with the newer model.  So the question is, which was yours, 1st or 2nd gen?