Also found a second variation of the grey paper card from The Downs Racetrack & Casino in Albuquerque, NM. There's slightly different spacing between the logo and text on the front and the "The Winner's Circle" line on the top of the back is totally different sizes. But the easiest way to spot the difference is the location of "CITY" and "ZIP" on the back. On one card they are aligned over one another, starting at the same place while on the other card "ZIP" starts at the end of "CITY".

Here's scans of the two variations...