49487 decodes as "4" - Buick / 9487 - Riviera Sport Coupe / 7H is the year and Flint Assembly Plant / 931004 is the sequential serial number This number will be the first 5 digits of the VIN, and will be the same on the engine, if it hasn't been replaced. Since the number on your engine is the same, this is a "number matching" car. 03C is the build week - Third week of March Paint is PP - Platinum Mist - trim is 668B is Black Vinyl Buckets (standard interior).