Did you see the SF Card Company sample that was recently on eBay? Here is a link:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150250162715
My understanding is that this is the only known sample design for that mold. This chip/mold is missing from my collection.

I haven't seen a Ewing sample chip for sale in a long time. The chip pictured is the only sample design I know of for that mold.