Primary Canon History
More than likely Peter didn't get the apartment until after the events involved of the emergence and fall of Gozer. He occupied it in the late 1980s, at least. Dana Barrett and her son Oscar were brief occupants during the New Year's Eve holiday. When Dana, Louis Tully, and Janine Melnitz were watching late night television, Janosz Poha appeared outside the apartment complex and kidnapped Oscar.
Secondary Canon History
During the Gozerian Terror Bear's rampage through Wall Street, it briefly passed by the building where Peter's apartment was located. It was also seen on a news report. Over a year later, while in Janine's mind, Egon Spengler and Roger Baugh briefly hid in Peter's apartment. It became apparent it was New Year's Eve 1989 as they overheard Janine and Louis on Peter's couch. While there, Egon realized things were tangible by the power of mind. They raced off to a Firehouse memory.
Behind the Scenes
The scene where Oscar is taken by Janosz was filmed at a studio set representing the exterior of the building. Bo Welch built the set - two exterior walls and a 10 foot tall ledge.  Chuck Gaspar built a special harness rig for the Deutschendorf twins portraying Oscar. It was a big leather diaper attached to a metal pole bolted down to the ledge. The diaper was hidden in the Deutschendorf's jumpsuit and the pole was hidden if their legs were kept in position. Just in case, several large airbags were placed below. The twins cooperated very well during filming. The twins' father Ron Deutschendorf stood on a ladder off-camera and made noises to make it look like the baby was looking out into the distance in the scene.  In order for the ledge shot in the kidnapping to be incorporated with the matte painting, Mark Vargo and his plate crew positioned a camera about 40 feet up along one side of the sound stage. The crew had to climb up a wooden ladder and walk along a very narrow catwalk. The Vistavision camera was too heavy to carry so it was pulled up on pulleys.
- In one of the rooms, you can clearly see the newspaper front pages from the "Ghostbusting montage" in the first film. They are the most visible in the scene when Peter returns from the museum.
- On the wall by the front door is the 1978 "Yankee Fever - Catch It" poster. Behind it on the right is an issue of the July 18, 1988 People Weekly.
- Near the desk on the wall are frames with the magazine and newspaper covers from the first film's montage - New York Post, USA Today, and Time.
- Below the frames is a Yankees pennant and leaned against the wall is a Ouija board
- On the desk are some Statue of Liberty collectibles such as a lamp based on the hand holding the torch.
- Near the doorway to the bathroom is the lamp that was on Peter's desk in the Firehouse in the first movie
- In his kitchen are bags of Utz The Crab Chip and Salt' n Vinegar flavors
- When Louis talks about Rita Hayworth, there is an orange box of Hi-C next to the popcorn
- Peter's apartment was filmed at residential lofts at 644 Broadway but the rooftop of the building was a matte painting.  In Chapter 16: Vigo 101, the Broadway and Bleecker Street signs outside the building are visible.
- The apartment was mentioned in Ghostbusters: The Video Game, during the Shandor's Island level, where Peter comments on the structure, "My apartment used to look like this."
- On page three of Ghostbusters Issue #8, a Statue of Liberty torch lamp like the one from the apartment is on the mantle.
- Chapter 14: A Tub Full of Slime
- Chapter 15: Peter's Place
- Chapter 16: Vigo 101
- Chapter 17: Fire-Trapped
- Chapter 18: In the Tunnel
- Chapter 19: Scaring the Straights
- Chapter 20: Kidnapping Oscar
- Chapter 28: World is Safe Again
- Eisenberg, Adam (November 1989). Ghostbusters Revisited, Cinefex magazine #40, page 25 footnote, 28-29. Cinefex, USA.
- Eisenberg, Adam (November 1989). Ghostbusters Revisited, Cinefex magazine #40, page 29. Cinefex, USA.
- Spook Central 644 Broadway
- Spook Central- 644 Broadway External shots location
- Spook Central- The Burbank Studios Special effects shots