At one time, a club member (Jim Follis) was attempting to track the Sahara plaques by serial number.
The website link is:
http://www.thechipgallery.com/plaque.htm

However, it hasn't been updated in 10 years. Still thought you would be interested in it.
The number of plaques decrease as $$$ increase. The biggest plaque ($1000) is worth as much as the rest of the set combined.

Enjoy your new addition.