10
That is difficult to say. How much safer is a car with a security belt, airbag, ...? One thing is sure: every bit helps.
You should at least rename the directories (which involves also the editing of mainfile.php) and have the .htaccess in place (see XOOPS 2.4.5).
Don't be shy to make modifications.
Copy simply mainfile.php to mainfile.old.php or something.
Then copy the directories to the new place or name.
Adapt the mainfile.php (watch out for not destroying punctuation).
Check if it works.
If not, replace mainfile.php by the copy and your site will run again.
Either way remove superfluous copies.