That sort of information is often available on-line these days, sometimes it takes a little sleuthing to find out.

Here's some general info for ya:

https://www.imdb.com/title/tt0044825/locations

You might also try the Nevada Film Office or the City of Las Vegas to see if they maintain a database of this sort of information. But perhaps in these Corona Days, with limited government staffing, it is better to wait until things get back to normal.

RKO was the movie company, then run by Howard Hughes, so expect to get nothing out of him. Warner Home Video now controls the rights, maybe they would know more? Call 'em up and ask to speak with Mr. Warner. If he doesn't come to the phone, ask to speak with his brother, Mr. Warner. Or Mr. Warner or Mr. Warner or . . . awwwww, nevvamind.