I agree... if the police take it seriously. There likely are < 100 El Caminos registered in St. Louis.
Likely an aficionado would be able to narrow it down, even if moderately customized. Late 70's? Early 80's?
Are the St. Louis traffic cams all redlight triggered? Or are there streaming ones? Anyway, somewhere the plates are visible.
Whether or not the eye witness report was accurate, it did appear to me in the video that the track of the vehicle altered slightly upon impact, so the driver had to have felt something.