Skip,
You are quite correct, however, Jack Webb would give you an elbow, for not mentioning his third show that displayed the amber-to-the-rear: EMERGENCY, with the caveat that "Rescue 51" was using a FS Twinsonic. Additionally, I believe the original "Dragnet," (1951-1959) used an in-car solid red to the front and next iteration (1967-1970) had a flashing red light from within the vehicle, but I'm fairly sure it was not a revolving light, aka, "fireball." This revival of show also displayed an amber-to-the-rear, on the few rear shots that Webb used. He felt that people didn't tune in to see vehicles, they wanted to see the people (sic. actors).
That last fact came from the best one of my grad school professors from the University of Cincinnati College Conservatory of Music, the late Frederick Ziv. For those of you who are my contemporaries, you might remember that after the credits rolled on such great shows as, "Highway Patrol," "Sea Hunt," "Bat Masterson," and many more, the full-screen credit of ZIV Television Productions, would pop up. He was an indefatigable executive producer, who was also close friends with Jack Webb and Rod Serling.
Steve