The extra car you see is a Checker cab - a drone car that didn't make the final game. The Coupe de Grace has a different roofline than originally planned in order to  differentiate it from the already completed '37 Ford.

Here are in-game shots of these cars -

bus1.jpg (86385 bytes) coup2.jpg (66868 bytes)jet0001.jpg (116291 bytes)     Backto CWR's C2 Car Ideas pageriv0005.jpg (98562 bytes) mach1.jpg (79040 bytes)

 stang1.jpg (94917 bytes) fairlane.jpg (77087 bytes)