Can the serial key of a retail version be checked by Run/regedit on Windows ?

[Googolplex]

There is no key file located on the DVD. The file only pops when you entered the key in the launcher.

And I'm sure they will remove the key validation with next update. Because there are many reasons:

1. AAMFP doesn't have this.
2. The "protection" is absolutely useless.
3. It will just cause frustration (like this).
4. It's an old game now.