I try to preprocess the content region of the Omega theme for a specific content type. So i have to check the content type inside the <subtheme>_alpha_preprocess_region(&$vars) function so that the preprocess modification only applies to that content type. In that case, we could make use of the menu_get_object() provided by the Drupal API.

preprocess-region.inc

<?php
function <subtheme>_alpha_preprocess_region(&$vars) {
  $menu_object = menu_get_object();
  if (isset($menu_object->type)) {
    if (<content type> == $menu_object->type) {
      // Do whatever you want
    }
  }
}

Done =)

Reference:

• Drupal Answers – How to get the content type in the zone/region tpl files?
• Drupal API – menu_get_object