Depending on the emisions package he could only have one cat and two 02 sensors. It's detailed in the shop manual for my 03. There is the federal emisions package and the California package if i remember right

 

All 03 rams with the hemi have a single cat, 04 and up have 2 cats

 

I do have 2 cats but it does say under the hood on a sticker labeled Emissions Control Information "Adheres to California Standards". I dont have any headers installed.

Parts/service, are the prices you mentioned per sensor or for a pair? Because there are 4 sensors if i have 2 cats correct? And should i buy directly from the dealer?