Sorry if this is getting annoying, but I figured I would update you all as I go (kind of thinking out loud via the forum) - I added the following code to target only the product info page around line 359 of 'includes/functions/html_output.php':

PHP Code:
    if (isset($_GET['main_page']) && $_GET['main_page'] == 'product_info')
    {
        $form .=  ' onSubmit="return confirm(\'Alert message goes here\')"';
    } 
Now all I should need to do is add my additional IF to determine whether or not the message should be printed and Voila!