Jeff...
Have you read the Strip History website? There isn't much there on LaRue's, but it does say that the Sands was a $5.5 million addition to the old restaurant...
http://www.lvstriphistory.com/ie/sands50.htm

Got out the trusty ol' phone books, not much help there either.

No listing in the State of NV directory from October of 1951.

The Southern NV directory from April of 1952 has La Rue Inc. LA Hwy. phone #6833. It's listed under Restaurants in the yellow pages, but no display ad. Not listed under Clubs or Cocktail Lounges (they didn't have listings for casinos )

The State of NV directory from August 1952 lists La Rue Inc. 3317 S. 5th, phone 6833.

Unfortunately, we don't have phone books from 1953 or 1954. There was no listing for LaRue's in 1955.