Originally there were 3 different variations listed in the guides for the paper cards from the Santa Fe Hotel Casino in Las Vegas, NV with a note that there were various size logos and spacing between text, etc. I think I now have enough of these to better list these cards so I've expanded the listings to now include 5 different variations that I've been able to identify.
Here's a description of each of the 5 variations I've been able to identify complete with scans to show the differences.
On the first card originally listed the word "of" in the last line on the reverse was indented but I've uncovered 2 versions of this particular card:
One card has a backward "S" in the Santa Fe logo with the top line longer than the bottom line.
The other card has a normal "S" in the Santa Fe logo with the top line shorter than the bottom line.
On the second card originally listed the word "of" in the last line on the reverse is aligned and there is no space between logo and address but I've uncovered 2 versions of this particular card:
On one card the line over "Identification No." is 26mm wide.
On the other card the line is 35mm wide
The last listed card is unchanged with no other variations discovered yet. On this card the word "of" in the last line on the reverse is aligned and there is a blank line between the top 2 lines of text on the reverse. There is also a wide space between the front logo and address.
Hopefully that helps having the variations documented. If you have something different, submit scans and I'll get it added.