A New Hope goes back to The Art of Star Wars which was published in November of 1979. But no it was never the title or subtitle of the real shooting script. It was the Adventures of Luke Starkiller as taken from the Journal of the Whills. Saga I. Star Wars. Shortened to Star Wars and there was no Episode IV at all period until 1979. The film itself wasn’t recut to episode IV until 1981.
According to a quote from Mark Hamill the film was at least acknowledged as Episode IV during production.