Your best bet is to:
* Check junkyards: This is the most reliable method. Visit local junkyards and physically compare the seats from other similar-era GM cars (like other mid-size models from the late 80s) to your Celebrity's seats. Pay attention to the mounting brackets and overall dimensions.
* Online forums and communities: Search for forums dedicated to 1987 Chevrolet Celebrities or classic GM cars. Members often discuss modifications and parts interchangeability. Someone might have already done this swap and documented it.
* Measure your seats: Take precise measurements of your Celebrity's seat mounting points and dimensions. Then, find similar measurements for seats from other GM models (using online resources or parts diagrams) to find a potential match.
Important Considerations:
* Year and Model: Even within the same body style, minor changes in seat design happened year to year.
* Trim Level: Different trim levels (base, upscale, etc.) might have different seat options, affecting compatibility.
* Mounting Brackets: The crucial factor is the mounting brackets. Even if the seats appear similar in size, different bracket designs can prevent a proper fit.
In short, there's no definitive answer without physical comparison. Start with your local junkyard and online communities for the most reliable information.