This has slowed done considerably and in the last three years, only one non-no grade 1870-CC has sold at auction.
In other words, population figures for AU58 1874-CC double eagles would suggest it isn’t rare.
But real world experience shows that properly graded CAC-caliber examples are in fact very scarce if not actually rare.
Prices for this date in all grades have risen as well.
I was recently offered an NGC MS60 example of this date for $20,000 and, gulp! After years of being undervalued, the 1874-CC is a sleeper no more an even nice AU58’s are selling at close to the $10,000 mark.
I have privately placed an AU58 and an MS60 and for both coins I had to pay what I believe were record prices.