// Remove Dynamic Widget Metabox from Custom Post Type Edit Screens
function remove_dynwid_box() {
 if ($current_user->user_level < 10){
   remove_meta_box('dynwid','custom_post_type','side'); 
 }
}
add_action('do_meta_boxes', 'remove_dynwid_box');

Source: 10+ Useful WordPress Code Snippets