Just found another variation of the 2nd issue card from Boomtown Casino in Biloxi, MS

Both cards have the WBM manufacturer mark and the Las Vegas 1-800-263-7777 phone number in the bottom right of 4 locations on the reverse -- that matches the original 2nd issue card description.

The original card listed has the Westbank phone# above the Las Vegas number and typically had a signature stripe although some cards didn't actually have a signature strip although there was a space for it.

The new found card has the Biloxi phone# above the Las Vegas number and has NO signature stripe with the reverse text moved up slightly.

Here's scans of the common front and the original and new found backs so you can see the difference.