I don't know if you can say it was a "prime" influence or that it blueprinted anything. But clearly it was something Lucas had on his mind when he was scripting the ending, just in terms of all those war films that kicking around in his head and all the cliches and plot devices they had. But it was more than just a "subconscious" memory, or whatever, because he was aware of it and used the movie's footage in the rough cut. Clearly it was something specific that he was looking at for shot design and such. Its not that the film is particularly great or anything, I just think when he was writing the space battle and was thinking "it should have a strategic shot, you know like they did in Dam Busters and that 633 Squadron film", he finally got around to checking out the films themselves and said "well, this footage here will be useful for temp shots." It may even be slightly random, because Lucas had a very early VCR of some sort and whenever there was an old war movie on television he would tape them and take notes, and then later cut the taped footage for the rough cut. So it might have just come down to the coincidence that PBS aired 633 Squadron at 2 AM one sunday night and Lucas happened to see it, and so it ended up being in the film.