1950's Highway Patrol Broderick Crawford used a Colt Cobra. The uniform CHP Officers used Colt Official Police 6". The only radio signal they used was "10-4".
Matthews had a Model 10 2" and his troopers had Model 10 6". Most bad guys seemed to carry the 4" Model 10. All the episodes I've seen that was it. Only Colt I remember seeing was in the hands of a bad guy and it was a 1911. In one episode, Matthews and his partner are pinned down behind a boulder by a guy with a rifle and way out of range. Matthews borrowed his guys six inch Model 10 and "tried" to make like a rifle with it...with no success.