Whatever you want to call it, it is without a doubt a recurring anomaly, so quite a few people would consider it a variation and collect it accordingly.
There seems to be more than just the 'pearly whites' and 'black tooth' varieties, too. After a quick search, I found the 2 different versions plus one that has Lou's teeth more delineated (far right in the scan)...
61gehrig.jpg
So, I guess collecting all of these depends on how much of a psycho variation collector you are.
