Cataloging All Coins At A Specific High Grade Low Pop

Maybe it is a natural progression, but now that I am collecting some low pop coins I find myself looking through Heritage sales and cataloging as many of the coins at that grade/TPG as I can find - to compare.

For instance, I recently bought a 1940-D MS67+FB PCGS merc at auction. It's pop is only 7 at PCGS. I was able to find 5 of the 6 OTHERS had been sold via Heritage ( mine wasn't ) at some point in the last 3.5 years. So I know what 6 of the 7 look like now and what all 6 have sold for etc. Mine's the best of the lot, of course. LOL But I also know that all 6 I found were CAC stickered. So at least 6/7 are considered "solid" or "hi-end" for 67+FB in that year/MM then.

It is pretty impressive that Heritage auctions so many of the top end coins sooner or later.

I was only able to find 1 other of another 4 pop merc, but of a 30 pop one I tracked down 26 unique ones via Heritage and a few other sources. Some had been re-auctioned as many as 5 times at Heritage since 2000. Found two of those 26 currently available at coastcoin by chance. Interesting to track as many down as possible.

Anyone else do this? Trying to ID all or most of the coins at a given grade. It was an interesting aside.