@Yosemite, the OP said he still lives in Cali on page 1 of this thread. There are other states that use the same emissions requirements as Cali. Maryland is one.
ooopps!!!
My memory is good…it’s just short!!!
Yosemite
The cat is the same for both 49 state and CA. What is different is certification. Some cheap cats will not certify in CA even though they are built to fed standards and the fed standards are the same as CA standards. Not sure why but it apparently has to do with the thickness of the platinum. You can have the required surface area but if it isn’t think enough, it wont last as long or something like that.
Also some companies simply have not bothered with getting the CA certification because of the cost.
Usually parts are much more expensive from a dealer even though they may be made in the same factory, to the same specs as the aftermarket cat. If you can get an aftermarket cat that is CA certified for less than a factory cat, do it. The CA certification certifies that the cat is identical to the one that came on the vehicle.
But make sure you really need one first.
Thank you all for your feedback. It really cleared up my confusion. Now I just need to find out how much a factory one costs. …oh I’m nervous 
~Sarah
@SMHDB
I urge you to talk to a reputable muffler shop. You’ll probably find that they have welded many cats on trucks just like yours
Also talk to the dealer about how much it costs to replace the cat
I think you’ll find the dealer price to be jaw dropping and eye opening
By the way, if you really want that factory cat, other shops besides the dealer can get it for you. But they’ll significantly mark up the price of the part