well yes - the first two happened in the lab, the second two aren't present in the entirety of the population and are a minority, ergo unless godidit they are relatively recent mutations which can be backtracked by some sleuthing to find out when and where they came from...
The first two didn't happen in the lab. The first one was the AIDS resistance mutation in humans. This has been around for centuries.
I also don't think it's clear that it provides any resistance to the Black Death. This was just a hypothesis to explain why models suggested it spread in Europe about 700 years ago.