Creating an add-on "product type book" for ZC 1.5

[mesnitu]

Hi there

in the tpl product info , I found myself in need of moving things a litle bit around, but I have a doubt about how to do it .
Ex: I remove the ISBN from the product details <ul id="productDetailsList"> , and I'm using the product variable $products_isbn to display it where I want. Also I want to display products details in two div's side by side.
So more or less like this :

<div id="left">
	<?php
		$zco_notifier->notify('NOTIFY_TPL_PRODUCT_BOOKX_INFO_DISPLAY_DOCPRODUCT_BEGIN');
		echo $authors_short_html;
                echo $publisher_short_html;
		echo $imprint_short_html;
		
		
?>
    </div> <!-- ends left -->
    <div id="right">
        <?php
        echo $bookx_extra_attributes_html;
                echo $publishing_date_html;
                echo $products_condition_html;
		echo $genres_html;
                echo $products_isbn;
        ?>
        
    </div><!-- ends right -->

So my doubt is if I'm safe playing around in the middle of this notifiers

$zco_notifier->notify('NOTIFY_TPL_PRODUCT_BOOKX_INFO_DISPLAY_DOCPRODUCT_BEGIN');

wahtever I want  

$zco_notifier->notify('NOTIFY_TPL_PRODUCT_BOOKX_INFO_DISPLAY_DOCPRODUCT_END', array('products_id' => $products_id_current));

Or this serves a order, that could break things up .

Thanks