I've just found out you can get the NPC of your choice by going to:
World of Warcraft Creatures | World of Warcraft @ Curse.com
And search for the creature you are looking for.
When you find the NPC you want, click on the small orange box, in doing so will show the xml, the xml in that shows the <display>#####</display> #= replace with number.
Example:
Let's say we want to find creature ID for Arvoar the Rapacious, we searched for him and found this:
Arvoar the Rapacious | a World of Warcraft Creature | World of Warcraft @ Curse.com
Now we need to click on the small orange button(looks like small RSS button), it will send us to the XML format.
http://wow.curse.com/database/creatures/...7/feed.xml
And we will search for
And we found this line:Code:<display>
<display>21394</display>
That's means 21394 is the modelID that's needed for creature_names.
Can't be simple then that!.