Re: your South Point Nevada Club ashtray --

Here's the MOGH/Chip Guide listing for that casino:
http://chipguide.themogh.org/cg_chip2.php?id=nvlan1&v=3079764128

Note that the ashtray (and matchbook, too) says "South Point, Nevada", rather than "Laughlin, Nevada" on your ashtray.

The place was open only a short time: 1975-78.

I wonder if this is the time period that the Post Office renamed the town as Laughlin?