I am venturing to guess that this postcard photo was taken in 1974 or 1976 as you will see an ELVIS sign on the Sahara Tahoe. He appeared 2 different times in 1974 (May and October) and his last appearances were in 1976 (May) - if it was the 1971 or 1973 appearances; Harvey's was painted green at that time, not the mustard color in this photo.

So much you can do to date photos - if I was good with older cards I could probably nail it.