you can make a copie of the skin you want.
And in the 'skin-without-a-post-date' you can delete this date part.

I've almost found the solution to my problem. I've added this to _main.php:

<?php if($disp != 'posts') { $Item->issue_date();  } ?>

So, the date will display one the "more" page.

Thing is, this is the opposite of what I want to do. I want the date to only be displayed on the main page of the site, not on the "more" pages.

I assume I just need to change 'posts' to something else. What do I need to change it to?