Such a feat would have been rare and remarkable, BMR, due not only to the distance between San Francisco and LA but also the terrain. The LA TV transmitters on Mount Wilson, while at a significant altitude (5700' above sea level), sit beneath even higher mountain ranges in the San Gabriel mountains. Those mountains effectively block direct reception of LA TV signals at most points due north or northeast. (Nearly the entire population base of the LA market is located south and west of Mount Wilson.) Along the coast heading northwest (San Francisco is not only north but considerably west of LA, the rugged Coast Range also serves to limit the reach of the LA signals.
The San Francisco stations are at much lower altitude - if memory serves, Mount Sutro is only 900 feet or so above sea level - and they, too, are somewhat blocked to the south and especially to the east by taller mountains.
In the analog days, if one could have set up a sensitive receiving station somewhere way up high in the Sierras east of Fresno, it might have been possible on occasion to catch signals from both LA and San Francisco (at distances more like 200 miles in each case), but that reception would have been inconsistent at best, and the physical challenges of getting a proper antenna (say, a huge rhombic for channels 2, 4 and 5) up to a site 12,000 feet or more would have been daunting.
What all those mountains did make possible was a network of microwave relays that brought LA and San Francisco TV stations to viewers in smaller communities in between via cable and translators. The LA TV market extends up the east side of the Sierras into the Owens Valley, more than 200 miles north of LA, thanks to microwave relays that existed as far back as the 1950s.
