The Style “D,” known as the “circus poster,” was completed by Struzan before the film’s initial release. The image harks back to the old Hollywood adventure films and was intended to be the first poster. But at the last minute that decision was changed and the poster did not go into circulation until the film’s 1978 re-release.
Reference: Sansweet, Stephen J. & Peter Vilmur, THE STAR WARS POSTER BOOK, San Francisco: Chronicle Books, 2005. Pages 25-29.