So you want the code to the pin it button without installing the button? If so just paste this code in the place of the url of the page you're pinning from. It should function as a pin it button without the button.
javascript:void((function(){var%20e=document.createElement('script');e.setAttribute('type','text/javascript');e.setAttribute('charset','UTF-8');e.setAttribute('src','http://assets.pinterest.com/js/pinmarklet.js?r='+Math.random()*99999999);document.body.appendChild(e)})());