A Family Way - S4-E5
Continuity mistake: When Dawson is coming down the stairs to talk to his parents in the living room, there is a shot of Gail and Mitch on the couch together. Gail is sitting in such a way that her legs are draped over Mitch's legs, and her right leg is specifically hanging over his right leg touching it. But in the next shot, they show Gail and Mitch from the other side of the couch; and suddenly she is sitting with her legs up, bent at the knees and Mitch has his right leg up. There wasn't enough time between shots for anyone to move.
Answer: It's the same apartment Joey had in NYC. Comparing it to the beginning of the Finale; you can tell it's exactly the same location, furnishings, Plasma TV etc. Apparently Chris was only living with her at HER apartment, and now Pacey has taken his place at the end. I guess this implies Pacey successfully started his own restaurant business in NYC as he had dreamed, to be with Joey.