If those wallet files were real, they would have never sold them.
Every single case you see on the internet is either malware that is intended to steal your coins or is simply an empty wallet file manually modified to look like it contains keys to popular addresses with large balances.
This, exactly this.
If you are foolish enough to believe in something like that then you are going to get hacked 100%. We will see you on this forum again, except you will be complaining about how you lost all your Bitcoins/Altcoins.
I really do not understand why people waste their time chasing uncatchable dreams. If something is too good to be true, then it most likely is.
Do not download any suspicious data, especially if it is promising you some sort of reward or similiar things.