Just uncovered a different variation of the 3rd issue red Caesars Emperors Club cards from the Caesars Casino in Atlantic City, NJ. There are currently 2 variations listed with different length bottom lines on the reverse, 54mm and 55mm wide. On the card with the 54mm wide bottom line on the back there are two different printings of the insert line on the front. One variation has "INSERT" being 7mm wide while the other is smaller at 6mm wide. The 3rd issue cards are those with a white reverse and a mag stripe.

Here's scans of the two variations with the different size INSERT's