Could it have been either of the
Street Rod games? It's possible the game wasn't ever sold with a model car, but unofficially paired with a model car by that single store to help drive sales or clear out inventory.
I see you said it's 3D so scratch Street Rod... Maybe
Stunt Driver? I had that on CD and I remember only 4 vehicles being available. The Shelby Mustang, a 60's VW Bug, an Iroc Z, and a Porche 911.
There was also
Stunts by Broderbund. Almost the exact same as Stunt Driver.
And then there was
Stunt Car Racer incase it was that. Good luck.