I remember the mid 1970s thru 1980s when a lot of the coins discussed here in this thread were in very large sales. They would be advertised in 2 full-page ads in Coin World
and Numismatic News
... like the bust half in platinum and the 1792 silver centered cent. Every week I couldn't wait to get my next Numismatic News
to see what obscure numismatic treasures would be auctioned or on private sale lists.