No, "Xenomorphs" is mentioned many times on the original posters:

NO LIVING THINGS LIKE THE XENOMORPHS SINCE THE DAWN OF TIME

XENOMORPHS ... ARE THEY HUMAN ... OR AWESOME THINGS FROM ANOTHER WORLD?

XENOMORPHS FROM ANOTHER WORLD

etc., etc. There are a ton of different posters duplicated in the pressbook.

Unless the Universal publicity guy(s) who wrote about ICFOS were fibbing (would they do that???), the word "Xenomorph" was "coined by the Greeks, who truly had a word for everything."