The trim tag would tell you if it came with bucket seats or not. That would be the only way to tell. The VIN is no help. Go to www.348-409.com. You can run the trim code on their site.

Several differances include the aluminum side trim as well as the trunk trim had a machined finish on the Super Sport as apposed to a satin finish on the regular Impala. I believe the SS Impala had bucket seats as well ar a "grab" handle above the glove box. Spinner type hubcaps were an option on both models. I'm not sure if there was a true SS hubcap for that year. Later year SS Impalas had their own caps with the SS logo in the center. The size and shape as well as the weight is the key factor between the two engines.The "big block" engine is larger in size and a lot heaver then the "small block.