You will find some threads on them in the archives. I bought one in 1998 along with 12 other nice chips, some unknown. I was told they were the only ones he had.
Robert E also bought the same package from him, again the only one. Spinetti also bought the same group of chips. If I remember right there was 15 of us that bought the same 13 chips.
More of the CC $5 came out, maybe a year or so later, on ebay.
Spinetti also bought some more CC $5 from the original seller about this time.
I was trying to keep track but its been too long and I'm too old. IMO, they are not rare!