If you're using administrator menu item Content -> article manager, you're using standard Joomla! com_content. (another way is looking on administrazor URL of content editing - if it contains "option=com_content") If you're using another component for articles (e.g. K2), you problably approach it from Components menu. Again, check option= variable in URL.

But more important is what you selected in Module manager -> News Pro GK4 -> Source of articles list.

After that, check JoomSEF -> Extension manager and check if you have installed newest SEF extension (default is Content) for articles component.

Also, when you perform changes, remember to delete and recreate all articles SEF URL's.