To be certain, you should:
* Consult your vehicle's repair manual: This will provide diagrams and precise location details specific to your year and model.
* Use a reliable online parts diagram: Many websites selling auto parts (like AutoZone, Advance Auto Parts, etc.) have detailed diagrams you can search by your year, make, and model. These diagrams often show the EGR valve's location.
Looking at pictures of the 5.9L Magnum engine online, coupled with these resources, will give you the most accurate identification. Be aware that accessing it might require removing some components depending on your specific truck's configuration.