If George had the idea of calling the first installment of his movies 'Episode IV: A New Hope' before 1979, it could be possible; however the evidence of the other names strongly suggest that George was still making up his mind on where the franchise should start and even how many chapters would be included. No doubt the success of the film helped in the decision. Maybe 'A New Hope' was an earlier idea, but it no doubt was his only one for the title.
If George had the idea of calling the first installment of his movies 'Episode IV: A New Hope' before 1979, it could be possible; however the evidence of the other names strongly suggest that George was still making up his mind on where the franchise should start and even how many chapters would be included. No doubt the success of the film helped in the decision. Maybe 'A New Hope' was an earlier idea, but it no doubt was his only one for the title.