Lynn - Before I answer can you please tell me what you remember about this other car? For example, interior color, vinyl top color, and any options you recall about the car. One option that might have caught your eye are the two "Light Monitoring" chrome monitors mounted on the fenders (Avatar @ left). You can also see them in Oaklyss beautiful 69. In addition, did it have only one outside mirror? A remote control mirror. These are easily distinguished by their bulky appearance.
In addition, where in Oklahoma did you see this car? And, did it look like the car in the pic below?
I have a feeling you can help me tie up some loose ends. Appreciate any info you can add.