These first gen builds are tricky because you could pretty much pick any option a la carte. However, all would get a dash plaque between the steering wheel and the ignition specifying the stage (1,2, or 3) and the serial number if it was a stage 3 for which there we none in 97. Note that these...
First gen Roush cars were built to order at satellite locations and installed options were up to the buyer. Many if not most did not have door jam stickers either. Also, the front body trim did not fit the Cobra. Only one cobra had them installed that I know of... I have a 95 RS3.