Found there are two variations of the slot card from the Kingdom Casino in Zimbabwe, Africa... These cards have a blank front with just a player or account number embossed but a printed back.

In the earlier variation, there is no space in the PO Box number line, it's "P.O.Box 90"

The later variation adds a space after P.O. so it now reads "P.O. Box 90"

Here's a link to the scans on the CG for the later variation
http://www.themogh.org/cg_showpic2.php?cg=137471

There's a slight difference in the fonts used on both cards so the spacing is slightly different as well.