get out a magnifying glass (or maybe a jewelers loupe)

On the right, just past the Sal Sagev Hotel building, you can see The Northern Club (1st casino license issued in Vegas in 1931), and next to it is the original Las Vegas Club (says BAR at the top of the sign). A little further down you can see the Frontier Club (actually, you can read CLU, and can sorta' make out Fron ).

On the left, kind of across from the Frontier Club, with just a little imagination, you can see the Boulder Club sign (similar in shape to the Las Vegas Club sign).

That's a great card!

As for the postcard folders... those pictures are just as much fun to look at as the real postcards. The picture of the Lucky 13 Club, that's in the magazine article, is from one of those folders...so is the Joe W. Brown's Horseshoe Club picture (I think).