You could add a custom field to the pages you want to show the copyright on and have your page.php (or header.php or index.php or whatever) look for it.
Example:
Set a custom field of “show_copyright” to “1” in the page editor.
In your page.php, right above <?php endwhile; endif; ?>, add this:
<?php
if ( get_post_meta($post->ID, 'show_copyright', true) ) {
?>
<div class="copy">
This is your copyright notice.
</div>
<?php
}
?>
Now, that said, there’s another way you could do it. Make a copy of your page.php, index,php, whatever, to a new name like “copyright.php”. Add your copyright message into that, and at the very top of the file, add this:
<?php
// Template Name: Copyright Notice
?>
Then, when editing your page, change the Page Template on the right to “Copyright Notice”. The trouble with this second method, though, is if you decide to change something in your website, you’ll need to edit both your page.php file (or index, blah blah) as well as your copyright.php.