Happy Days' "first episode" was on "Love, American Style" and aired on Feb 25, 1972. American Graffiti opened August 1, 1973 However after Graffiti made the big bucks, ABC picked it up as a series.
judging from the track record of Star Wars TV shows, I don't think this is that secure of an investment. Will Bea Arthur appear in the new show? She stole the Holiday Special.