i wouldn't worry quite so much. the private contractors basically have to adhere to the same standards as the government. there are certain jobs available for people who aren't US citizens. anything that requires a "secret" or higher clearance automatically must be a US cit-only job. if you go to the website (or to usajobs.com for govt jobs) and search for various positions, it will tell you right in the listing what the nationality rqmts are.
if anything i would question your friend for not be diligent in his research of what the job was and search for the listing directly from Raytheon. even if he got the description from the headhunter it would only be prudent to search it out on your own.