Maybe I am misunderstanding your question. You stated that your goal is to "check the plausibility of two .dat files containing a valuable address". Do you mean two different wallets having the same address that has bitcoins?
Perhaps I'm mistaken, but the question posted by OP feels a bit like an
XY Problem.
Trying to read between the lines and guess at what's actually going on here, MAYBE what OP is actually saying is:
"I've been given the opportunity to purchase 2 wallets.dat files. I've been told that each of these wallet.dat files contains a different address that has received a significant sum of bitcoins. I've also been told that the reason these wallet.dat files are for sale is that the password has been forgotten and therefore the original owner is no longer able to access the Bitcoins. I'm attempting to use various heuristics to measure for myself the amount of risk that these addresses were artificially added to the wallet without the appropriate private key instead of having been generated by the wallet (with the private key), as a method of determining how much I'm willing to pay for the possibility. One of the things I've noticed is that neither of these wallets has a nice even, pretty number of addresses that might be considered to be a natural breakpoint for a default number of addresses generated when first installed, instead they have 201 and 1001 addresses. I'm curious about what the actual default number of addresses is for freshly installed wallets at various times in the past because I think it might help me understand if I need to be concerned about the fact that these wallets have 201 addresses and 1001 addresses. Knowing when various changes were made to the default number of addresses, and comparing those dates to the dates of when the transactions were sent to the addresses in question might also help me determine if the story I've been told about these wallets makes any sense at all. Can someone please share with me the date of when Bitcoin Core began using compressed addresses by default at the time of installation, and what the default quantity of addresses generated at installation have been each time it changed (as well as the dates when those changes happened)?"That's my best guess. I could be wrong.