Hi Bob,
Since I only collect Harrahs cards by the prefix # I hadn't paid much attention to the backs. I only have about 200 new Harrahs cards but I checked them all and this is what I came up with. I have at least one gold. platinum, diamond and 7 stars with the 5 phone numbers on the bottom line. Most interesting is that ALL gold and platinum cards have the 800-4-REWARD number and ALL diamond cards have the 877-7-Player number, no exceptiions.

JRS