* The specific GM brand: (Chevrolet, Buick, GMC, Cadillac, Pontiac (discontinued), Oldsmobile (discontinued), etc.)
* The specific model: (e.g., Chevrolet Impala, Buick Roadmaster, Cadillac DeVille)
* The specific body style: (sedan, coupe, convertible, wagon, SUV, etc.)
* The year or range of years: (e.g., 1965, 1980-1985)
With this specific information, you might be able to find production numbers through archival research, enthusiast websites dedicated to specific GM models, or possibly by contacting GM's historical archives (though access may be limited).