For registration of new Joomla users, SCLogin simply redirects to whatever component you've set up with the "Registration Component" option. We aren't doing to work to display the registration form. Whether the reCaptcha shows in the registration component depends on how you've configured your site. For Joomla, for instance, you'll have to enable the reCaptcha plugin and also go into your Global Configuration area to turn it on for the front-end.
-Melissa