http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=6151844965&ssPageName=STRK:MEWA:IT

Most of you will be aware this is a regular chip. For those that dont, there was an issue of 100 'normal' chips and 100 'reversed'.

I also wouldnt go so far as to say it was 'RARE' - they can still be found.