As of July 1, 2009, Slots a Fun is no longer Slots a Fun. It was taken over by Circus Circus. This is from a July 2009 press release.

"It's offical. Slots A Fun has lost the name and Circus Circus has the space and rights to gaming there.

The name has been changed to Slots A Fun at Circus Circus."

New ownership, new name qualifies as obsolete doesn't it?

Regarding the missing $200, is it a prototype? Is there only one in existence or was it a readily available $200 that the public could get?

If it's not in a price guide, I'm guessing it wasn't available to the public.