you cant add your own code to go central I'm sure. When Pinterest give you this code they expect a professional developer site ( hand coded) not a CMS.
I would chat with support and see if there are alternative solutions.
Or contact Pinterest support as well.
Thanks for your comment! As you know, currently GoCentral does not support editing the <head> section of a website. The request for Pinterest verification as a feature has been passed on to the product team. We don't have a estimate at this point as to when this feature will be available but please stay tuned. Thanks!
Just wanted to let you know that we recently launched the opportunity to add your website to Pinterest. Please see the solution at the bottom of this post for more information. Thanks!