What versions before v.04 that is encrypted and produce iteration less than 25000? Can you name one or two just to have a glimpse of which ones you meant.
If you're asking this question to @lucas85moose (who made post above yours), then you wasted your time. That account is used for SEO spam purpose (the spam link is hidden inside 1pt text) and i bet his reply is AI generated.
What about the release or testing versions before this version ? Because I have seen a lot of wallets with count less than 25000, are they all fake ?
I don't know your ultimate goal. But these days, i would just assume all wallet.dat that can be found on internet as fake. I also would like to re-share this statement by one of Bitcoin Core developer/contributor.
The wallet file isn't fake per se, nor are the transactions it shows. What's fake about it is that it doesn't contain the private keys it claims it does.
The method of identification is to look at the corresponding version of the wallet code, check the data consistency, time, field, type, structure, It looks very complicated.
It actually is not that complicated. You don't need to check any data consistency, time, etc. You don't need to check any of the things you mentioned. You also don't really need to look at the wallet code because the data that they are manipulating doesn't change frequently, if ever. In fact, the specific database fields that are being modified will likely never change in order to maintain backwards compatibility with older wallet versions.
What the authors have done here is simply add fields which represent encrypted keys. These fields contain the pubkey and the encrypted private key which will typically just look like random data (because that's the point of encryption). What the authors have done is just create a field that contains the pubkey and random data (or in this case, a string) as the private key.
It is impossible for anyone (technical or not, professional or not) to identify that the wallet is "fake" by simply looking at it (besides the fact that common sense tells you its a scam). If done correctly, the supposed encrypted key will be garbage data and its veracity cannot be determined without knowing the decryption key. Of course, if it's just zeroes or some other obvious non-random data, then it can be easily determined. You can inspect the data of a wallet.dat file using BDB 4.6's db_dump tool.