Looks like they are from the same machine. the die chips could happen in a batch that new ones may have showed up later on. So they were probably from the same machine setup. Die chips are a permanent die event. Once there, they will not go away. But new ones could be added as the die ages. What is a die chip? It is when part of the metal breaks off of the die, leaving a void. Then coins will be filled on the coins struck with that die leaving the raised die chip on the coins. So die chips do not go away, but can continue to develop new die chips. They are a common die event, and serve as a marker for a die. But only important on a die variety, or if you need to see a pattern on a certain die, like what you did for these coins.
CoopHome:
What is a die chip on a coin? a void on the die that when a coin is struck, it will show a raised area on a coin