If your widget contains references to non-secure URLs (e.g. HTTP instead of HTTPS), it may not display in the Sitebuilder, depending on how the browser handles non-secure content. However, the widget will display on the live version of your site provided that you have not enabled SSL.
If you have opted to turn SSL on for your site, then, you will need to update the third-party codes you have added to include https://. Otherwise, you will get a warning message on your live site saying that your content is insecure or the widget may not show up on the published version of your site.
Note: Any third party content you add to your site should be securely hosted, regardless of whether or not SSL is enabled on your domain. This will ensure that your content displays in all browsers and your visitors will not receive any security warnings. Browsers are going to become increasingly strict in this regard, so the best approach is to ensure that all content on your site is secure (HTTPS).