First off the Stardust Lido Sign says "Lido 1976" so that gives an indication what year.

From what I read, the Riviera expansion (seen in this picture) didn't happen until the early 80's so that would explain the cars next to where the picture was taken.

Also in Ricky's Picture you can see the Palm Tree La Concha Motel (left hand side) you can see the same Palm Tree in the picture below.

The Red line would indicate an approximate spot on the parking lot where the picture was taken from.