In the 1940's, when the Golden Nugget was being built, the Boulder Drug Co moved to 1700 Las Vegas Blvd. (West side of LVB at Oakley St).
It is still there and is called "White Cross Drug Store". They still have the original dining/soda fountain counter and I swear the last time I was in there (years ago) they still had a canister of Lincoln Logs on the shelf from the 1960's for sale.
The dining counter (called Tiffany's) is popular with downtown graveyard casino employees that get off of work and want a quiet, inexpensive place to have a sit-down breakfast. Don't think it's open 24 hours anymore - neighborhood has gotten too dicey, but it is a cool "blast from the past".
Plus, I've heard they still make a fantastic old fashioned chocolate malt!

Oh yes, after you see "The Cross", don't forget to head east on Oakley (across the street) to "Luv-Its" Frozen Custard - awesome!