Download [Only registered and activated users can see links. ] (click link for info) and use it open one of the map files (drag & drop into the shortcut you create to it on your desktop).
Click the Details tab. Below is (only a small part of) an example of what you will see:

Code:
Please Login or Register to see the links
Do you see the word "locked" as highlighted in red above? If so, the map is locked. If not, the map is unlocked.